Vessel sealer and divider

ABSTRACT

An endoscopic bipolar forceps includes an elongated shaft having opposing jaw members at a distal end thereof. The jaw members are movable relative to one another from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue therebetween. The forceps also includes a source of electrical energy connected to each jaw member such that the jaw members are capable of conducting energy through tissue held therebetween to effect a seal. A generally tube-like cutter is included which is slidably engaged about the elongated shaft and which is selectively movable about the elongated shaft to engage and cut tissue on at least one side of the jaw members while the tissue is engaged between jaw members.

CROSS REFERENCE TO RELATED APPLICATION:

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 10/116,944 filed on May 16, 2001 by Dycus, et al. entitled“VESSEL SEALER AND DIVIDER” which is a continuation-in-part of PCTApplication Serial No. PCT/US02/01890 filed on Jan. 25, 2002 by Dycus,et al. entitled “VESSEL SEALER AND DIVIDER” which is acontinuation-in-part of PCT Application Serial No. PCT/US01/11340 filedon Apr. 6, 2001 by Dycus, et al. entitled “VESSEL SEALER AND DIVIDER”,the entire contents of all of these applications are hereby incorporatedby reference herein.

BACKGROUND

[0002] The present disclosure relates to an electrosurgical instrumentand method for performing endoscopic surgical procedures and moreparticularly, the present disclosure relates to an open or endoscopicbipolar electrosurgical forceps and method for sealing and/or cuttingtissue.

[0003] 1. Technical Field

[0004] A hemostat or forceps is a simple plier-like tool which usesmechanical action between its jaws to constrict vessels and is commonlyused in open surgical procedures to grasp, dissect and/or clamp tissue.Electrosurgical forceps utilize both mechanical clamping action andelectrical energy to effect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue.

[0005] Over the last several decades, more and more surgeons arecomplimenting traditional open methods of gaining access to vital organsand body cavities with endoscopes and endoscopic instruments whichaccess organs through small puncture-like incisions. Endoscopicinstruments are inserted into the patient through a cannula, or port,that has been made with a trocar. Typical sizes for cannulas range fromthree millimeters to twelve millimeters. Smaller cannulas are usuallypreferred, which, as can be appreciated, ultimately presents a designchallenge to instrument manufacturers who must find ways to makesurgical instruments that fit through the cannulas.

[0006] Certain endoscopic surgical procedures require cutting bloodvessels or vascular tissue. However, due to space limitations surgeonscan have difficulty suturing vessels or performing other traditionalmethods of controlling bleeding, e.g., clamping and/or tying-offtransected blood vessels. Blood vessels, in the range below twomillimeters in diameter, can often be closed using standardelectrosurgical techniques. However, if a larger vessel is severed, itmay be necessary for the surgeon to convert the endoscopic procedureinto an open-surgical procedure and thereby abandon the benefits oflaparoscopy.

[0007] Several journal articles have disclosed methods for sealing smallblood vessels using electrosurgery. An article entitled Studies onCoagulation and the Development of an Automatic Computerized BipolarCoagulator, J. Neurosurg., Volume 75, July 1991, describes a bipolarcoagulator which is used to seal small blood vessels. The article statesthat it is not possible to safely coagulate arteries with a diameterlarger than 2 to 2.5 mm. A second article is entitled AutomaticallyControlled Bipolar Electrocoagulation—“COA-COMP”, Neurosurg. Rev. ( 1984), pp.187-190, describes a method for terminating electrosurgical powerto the vessel so that charring of the vessel walls can be avoided.

[0008] As mentioned above, by utilizing an electrosurgical forceps, asurgeon can either cauterize, coagulate/desiccate and/or simply reduceor slow bleeding, by controlling the intensity, frequency and durationof the electrosurgical energy applied through the jaw members to thetissue. The electrode of each jaw member is charged to a differentelectric potential such that when the jaw members grasp tissue,electrical energy can be selectively transferred through the tissue.

[0009] In order to effect a proper seal with larger vessels, twopredominant mechanical parameters must be accurately controlled—thepressure applied to the vessel and the gap distance between theelectrodes—both of which are affected by the thickness of the sealedvessel. More particularly, accurate application of pressure is importantto oppose the walls of the vessel; to reduce the tissue impedance to alow enough value that allows enough electrosurgical energy through thetissue; to overcome the forces of expansion during tissue heating; andto contribute to the end tissue thickness which is an indication of agood seal. It has been determined that a typical fused vessel wall isoptimum between 0.001 and 0.005 inches. Below this range, the seal mayshred or tear and above this range the lumens may not be properly oreffectively sealed.

[0010] With respect to smaller vessel, the pressure applied to thetissue tends to become less relevant whereas the gap distance betweenthe electrically conductive surfaces becomes more significant foreffective sealing. In other words, the chances of the two electricallyconductive surfaces touching during activation increases as the vesselsbecome smaller.

[0011] Electrosurgical methods may be able to seal larger vessels usingan appropriate electrosurgical power curve, coupled with an instrumentcapable of applying a large closure force to the vessel walls. It isthought that the process of coagulating small vessels is fundamentallydifferent than electrosurgical vessel sealing. For the purposes herein,“coagulation” is defined as a process of desiccating tissue wherein thetissue cells are ruptured and dried. Vessel sealing is defined as theprocess of liquefying the collagen in the tissue so that it reforms intoa fused mass. Thus, coagulation of small vessels is sufficient topermanently close them. Larger vessels need to be sealed to assurepermanent closure.

[0012] U.S. Pat. No. 2,176,479 to Willis, U.S. Pat. Nos. 4,005,714 and4,031,898 to Hiltebrandt, U.S. Pat. Nos. 5,827,274, 5,290,287 and5,312,433 to Boebel et al., U.S. Pat. Nos. 4,370,980, 4,552,143,5,026,370 and 5,116,332 to Lottick, U.S. Pat. No. 5,443,463 to Stern etal., U.S. Pat. No. 5,484,436 to Eggers et al. and U.S. Pat. No.5,951,549 to Richardson et al., all relate to electrosurgicalinstruments for coagulating, cutting and/or sealing vessels or tissue.However, some of these designs may not provide uniformly reproduciblepressure to the blood vessel and may result in an ineffective ornon-uniform seal.

[0013] Many of these instruments include blade members or shearingmembers which simply cut tissue in a mechanical and/or electromechanicalmanner and are relatively ineffective for vessel sealing purposes. Otherinstruments rely on clamping pressure alone to procure proper sealingthickness and are not designed to take into account gap tolerancesand/or parallelism and flatness requirements which are parameters which,if properly controlled, can assure a consistent and effective tissueseal. For example, it is known that it is difficult to adequatelycontrol thickness of the resulting sealed tissue by controlling clampingpressure alone for either of two reasons: 1) if too much force isapplied, there is a possibility that the two poles will touch and energywill not be transferred through the tissue resulting in an ineffectiveseal; or 2) if too low a force is applied the tissue may pre-maturelymove prior to activation and sealing and/or a thicker, less reliableseal may be created.

[0014] As mentioned above, in order to properly and effectively seallarger vessels, a greater closure force between opposing jaw members isrequired. It is known that a large closure force between the jawstypically requires a large moment about the pivot for each jaw. Thispresents a challenge because the jaw members are typically affixed withpins which are positioned to have a small moment arms with respect tothe pivot of each jaw member. A large force, coupled with a small momentarm, is undesirable because the large forces may shear the pins. As aresult, designers must compensate for these large closure forces byeither designing instruments with metal pins and/or by designinginstruments which at least partially offload these closure forces toreduce the chances of mechanical failure. As can be appreciated, ifmetal pivot pins are employed, the metal pins must be insulated to avoidthe pin acting as an alternate current path between the jaw memberswhich may prove detrimental to effective sealing.

[0015] Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another which may result in a short circuitand a small closure force may cause pre-mature movement of the issueduring compression and prior to activation.

[0016] Typically and particularly with respect to endoscopicelectrosurgical procedures, once a vessel is sealed, the surgeon has toremove the sealing instrument from the operative site, substitute a newinstrument through the cannula and accurately sever the vessel along thenewly formed tissue seal. As can be appreciated, this additional stepmay be both time consuming (particularly when sealing a significantnumber of vessels) and may contribute to imprecise separation of thetissue along the sealing line due to the misalignment or misplacement ofthe severing instrument along the center of the tissue sealing line.

[0017] Several attempts have been made to design an instrument whichincorporates a knife or blade member which effectively severs the tissueafter forming a tissue seal. For example, U.S. Pat. No. 5,674,220 to Foxet al. discloses a transparent vessel sealing instrument which includesa longitudinally reciprocating knife which severs the tissue oncesealed. The instrument includes a plurality of openings which enabledirect visualization of the tissue during the sealing and severingprocess. This direct visualization allows a user to visually andmanually regulate the closure force and gap distance between jaw membersto reduce and/or limit certain undesirable visual effects known to occurwhen sealing vessels, thermal spread, charring, etc. As can beappreciated, the overall success of creating an effective tissue sealwith this instrument is greatly reliant upon the user's expertise,vision, dexterity, and experience in judging the appropriate closureforce, gap distance and length of reciprocation of the knife touniformly, consistently and effectively seal the vessel and separate thetissue at the seal along an ideal cutting plane.

[0018] U.S. Pat. No. 5,702,390 to Austin et al. discloses a vesselsealing instrument which includes a triangularly-shaped electrode whichis rotatable from a first position to seal tissue to a second positionto cut tissue. Again, the user must rely on direct visualization andexpertise to control the various effects of sealing and cutting tissue.

[0019] Thus, a need exists to develop an electrosurgical instrumentwhich effectively and consistently seals and separates vascular tissueand solves many of the aforementioned problems known in the art.

SUMMARY

[0020] The present disclosure relates to an endoscopic bipolar forcepsincludes an elongated shaft having opposing jaw members at a distal endthereof. The jaw members are movable relative to one another from afirst position wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween. The forceps also includes asource of electrical energy connected to each jaw member such that thejaw members are capable of conducting energy through tissue heldtherebetween to effect a seal. A generally tube-like cutter is includedwhich is slidably engaged about the elongated shaft and which isselectively movable about the elongated shaft to engage and cut tissueon at least one side of the jaw members while the tissue is engagedbetween jaw members.

[0021] Preferably, the cutter includes a U-shaped notched blade and theblade is recessed from the outer periphery of the cutter. In oneembodiment, the blade includes a bevel having opposing sharp edgesdisposed within the proximal most portion of the U-shaped blade. Inanother embodiment, the U-shaped blade includes opposing serrated edgesto facilitate severing the tissue. Alternatively, the U-shaped notch caninclude opposing substantially dull edges and the cutter is rapidlyadvanced through the tissue under a spring pressure, hydraulic pressure,electrical actuator or the like.

[0022] In another embodiment, the cutter includes a remotely operableactuator for selectively deploying the cutter to sever tissue.Preferably, the actuator is a trigger. In yet another embodiment, thecutter rotates as the cutter severs tissue on at least one side of thejaw members while the tissue is engaged between jaw members.

[0023] The cutter may be designed to mechanically cut tissue,electromechanically cut tissue (i.e., RF energy, ultrasonic energy)and/or thermo-mechanically cut tissue depending upon a particularpurpose. In one particular embodiment, the cutter is connected to asource of electrosurgical energy and the cutter severs tissue in amechanical and electrosurgical manner.

[0024] Preferably, the cutter includes a cutting area having a U-shapednotched blade at a proximal end thereof and a pair of arms at a distalend thereof. The arms are dimensioned to feed tissue into the cuttingarea into contact with the U-shaped notched blade upon distal movementof the cutter.

[0025] Another embodiment of the present invention includes an elongatedshaft having opposing jaw members at a distal end thereof. One of thejaw members is movable relative to the other jaw member from a firstposition wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween. An electrically conductive outersleeve is included which at least partially surrounds the shaft. Theouter sleeve mechanically cooperates with the movable jaw member topivot the movable jaw member from the first to second positions. Theforceps also includes an actuator for selectively moving the outersleeve to electrosurgically energize and pivot the jaw members. The jawmembers may be closed and energized simultaneously or independently bythe actuator.

[0026] In one embodiment, the movable jaw member includes a protrusionwhich mechanically interfaces with the outer sleeve such that when thesleeve moves in a first direction, the movable jaw member pivots to thefirst position and is electrically isolated from the outer sleeve.Moreover, when the sleeve moves in a second direction, the movable jawmember pivots into the second position and the outer sleeveelectrosurgically energizes the movable jaw member.

[0027] Preferably, at least one of the jaw members includes a knifechannel for reciprocating a knife therethrough and the distal end of theelongated shaft houses the knife within a corresponding knife cavity.The knife is prevented from reciprocating through the knife channel whenthe jaw member is in the first position and the knife channel and theknife cavity are out of alignment.

[0028] Preferably, the jaw members include opposing conductive sealingsurfaces disposed on the inner facing surfaces of the jaw members and atleast one of the jaw members is made from a hard anodized aluminumhaving high dielectric properties. Each jaw member includes an outerperipheral surface coated with a material which reduces tissueadherence. The coating is selected from a group of materials consistingof: TiN, ZrN, TiAlN, CrN, Ni200, Ni201, inconel 600, and resinousfluorine containing polymers or polytetrafluoroethylene.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various embodiments of the subject instrument are describedherein with reference to the drawings wherein:

[0030]FIG. 1A is a left, perspective view of an endoscopic bipolarforceps showing a housing, a shaft and an end effector assemblyaccording to the present disclosure;

[0031]FIG. 1B is a left, perspective of an open bipolar forcepsaccording to the present disclosure;

[0032]FIG. 2 is a top view of the forceps of FIG. 1;

[0033]FIG. 3 is a right, side view of the forceps of FIG. 1;

[0034]FIG. 4 is a right, perspective view of the forceps of FIG. 1showing the rotation of the end effector assembly about a longitudinalaxis “A”;

[0035]FIG. 5 is a front view of the forceps of FIG. 1;

[0036] FIGS. 6 is an enlarged view of the indicated area of detail ofFIG. 5 showing an enhanced view of the end effector assembly detailing apair of opposing jaw members;

[0037]FIG. 7 is an enlarged, left perspective view of the indicated areaof detail of FIG. 1 showing another enhanced view of the end effectorassembly;

[0038]FIG. 8 is an enlarged, right side view of the indicated area ofdetail of FIG. 3 with a pair of cam slots of the end effector assemblyshown in phantom;

[0039]FIG. 9 is a slightly-enlarged, cross-section of the forceps ofFIG. 3 showing the internal working components of the housing;

[0040]FIG. 10 is an enlarged, cross-section of the indicated area ofdetail of FIG. 9 showing the initial position of a knife assemblydisposed within the end effector assembly;

[0041]FIG. 11 is an enlarged, left perspective view showing the housingwithout a cover plate and the internal working components of the forcepsdisposed therein;

[0042]FIG. 12 is an exploded, perspective view of the end effectorassembly, the knife assembly and the shaft;

[0043]FIG. 13 is an exploded, perspective view of the housing and theinternal working components thereof with the attachment of the shaft andend effector assembly to the housing shown in broken line illustration;

[0044]FIG. 14 is greatly-enlarged, top perspective view of the endeffector assembly with parts separated showing a feed path for anelectrical cable through the top jaw member;

[0045]FIG. 15 is a longitudinal, cross-section of the indicated area ofdetail of FIG. 9;

[0046]FIG. 16 is an enlarged, top perspective view of the end effectorassembly showing the feed path for the electrical cable through theopposing jaw members and the proximal attachment of the knife assemblyto a longitudinally-reciprocating knife tube disposed within the shaft;

[0047]FIG. 17 is an enlarged, top perspective view of the end effectorassembly showing the feed path for the electrical cable along alongitudinally-disposed channel defined within the outer periphery ofthe shaft;

[0048]FIG. 18A is a greatly-enlarged, side perspective view of thehousing without the cover plate showing the feed path for the electricalcable through a rotating assembly adjacent to a distal end of thehousing;

[0049]FIG. 18B is a greatly-enlarged, side perspective view of thehousing without the cover plate showing the feed path for the electricalcable through a rotating assembly with the shaft mounted within thehousing;

[0050]FIG. 19 is a greatly-enlarged, rear view of the rotating assemblyshowing an internally-disposed stop member;

[0051]FIG. 20 is a perspective view of the forceps of the presentdisclosure shown in position to grasp and seal a tubular vessel orbundle through a cannula;

[0052]FIG. 21 is a slightly-enlarged, cross-section of the internal,cooperative movements of a four-bar handle assembly disposed within thehousing which effects movement of the jaw members relative to oneanother;

[0053]FIG. 22 is a greatly-enlarged, cross-section showing the initialmovement of a flange upon activation of the four-bar handle assemblyshown in phantom illustration;

[0054]FIG. 23 is a greatly-enlarged, side view showing the resultingcompression movement of a coil spring in reaction to the movement of thefour-bar handle assembly;

[0055]FIG. 24 is a greatly-enlarged, side view showing the proximalmovement of a cam-like drive pin of the end effector assembly as aresult of the proximal compression of the coil spring of FIG. 23 which,in turn, moves the opposing jaw members into a closed configuration;

[0056]FIG. 25 is a greatly-enlarged, cross-section showing the knifeassembly poised for activation within a cannula;

[0057]FIG. 26 is a top perspective view showing the opposing jaw membersin closed configuration with a tubular vessel compressed therebetween;

[0058]FIG. 27 is an enlarged perspective view of a sealed site of atubular vessel showing a preferred cutting line “B-B” for dividing thetubular vessel after sealing;

[0059]FIG. 28 is a longitudinal cross-section of the sealed site takenalong line 28-28 of FIG. 27;

[0060]FIG. 29 is a side view of the housing without a cover plateshowing the longitudinal reciprocation of the knife tube upon activationof a trigger assembly;

[0061]FIG. 30 is a greatly-enlarged, cross-section of the distal end ofthe instrument showing longitudinal reciprocation of the knife assemblyupon activation of the trigger assembly;

[0062]FIG. 31 is a longitudinal cross-section of the tubular vesselafter reciprocation of the knife assembly through the sealing site alongpreferred cutting line “B-B” of FIG. 28;

[0063]FIG. 32 is a greatly-enlarged, side view showing movement of theflange upon re-initiation of the handle assembly along a predefined exitpath which, in turn, opens the opposing jaw members and releases thetubular vessel;

[0064]FIG. 33 is a greatly enlarged, perspective view showing oneparticular stop member configuration on one of the vessel sealingsurfaces of one of the jaw members;

[0065]FIG. 34A is an internal side view of the housing showing oneembodiment of a handswitch for use with the present disclosure;

[0066]FIG. 34B is a schematic illustration of an alternate embodiment ofthe handswitch according to the present disclosure; and

[0067]FIG. 34C is a schematic illustration of another embodiment of thehandswitch according to the present disclosure;

[0068]FIGS. 35A and 35B are schematic illustrations of heating blocksaccording to the present disclosure;

[0069]FIGS. 35C and 35D are schematic illustrations jaw members withintermittent sealing surface patterns;

[0070]FIG. 36 shows one embodiment of a slide tube cutter in accordancewith the present invention;

[0071]FIG. 37A shows one embodiment of a laparoscopic forceps with theslide tube cutter of FIG. 36 wherein the slide tube cutter is poised forlongitudinal reciprocation of U-shaped notched blade through a vesselalong a seal plane “B-B”;

[0072]FIG. 37B shows another embodiment of a laparoscopic forceps withthe slide tube cutter of FIG. 36 wherein the slide tube cutter is poisedfor longitudinal reciprocation and rotation of U-shaped notched bladethrough a vessel along a seal plane “B-B”;

[0073]FIGS. 38A and 38B show tow alternate embodiments of the slide tubecutter in accordance with the present disclosure;

[0074]FIG. 39A shows a laparoscopic forceps having a unilateral closuremechanism shown in open configuration;

[0075]FIG. 39B shows a laparoscopic forceps having a unilateral closuremechanism shown in closed configuration;

[0076]FIG. 39C shows a laparoscopic forceps having a unilateral closuremechanism shown in open configuration with a knife blade andcorresponding knife channel shown in phantom; and

[0077]FIG. 39D shows a laparoscopic forceps having a unilateral closuremechanism shown in closed configuration with a knife blade andcorresponding knife channel shown in phantom.

DETAILED DESCRIPTION

[0078] Referring now to FIGS. 1-6, one embodiment of a bipolar forceps10 is shown for use with various surgical procedures and generallyincludes a housing 20, a handle assembly 30, a rotating assembly 80, atrigger assembly 70 and an end effector assembly 100 which mutuallycooperate to grasp, seal and divide tubular vessels and vascular tissue420 (FIG. 20). Although the majority of the figure drawings depict abipolar forceps 10 for use in connection with endoscopic surgicalprocedures, an open forceps 10′ is also contemplated for use inconnection with traditional open surgical procedures and is shown by wayof example in FIG. 1A. For the purposes herein, the endoscopic versionis discussed in detail, however, it is contemplated that open forceps10′ also includes the same or similar operating components and featuresas described below.

[0079] More particularly, forceps 10 includes a shaft 12 which has adistal end 14 dimensioned to mechanically engage the end effectorassembly 100 and a proximal end 16 which mechanically engages thehousing 20. Preferably, shaft 12 is bifurcated at the distal end 14thereof to form ends 14 a and 14 b which are dimensioned to receive theend effector assembly 100 as best seen in FIGS. 7 and 12. The proximalend 16 of shaft 12 includes notches 17 a (See FIGS. 23 and 29) and 17 b(See FIGS. 11, 12 and 13) which are dimensioned to mechanically engagecorresponding detents 83 a (FIG. 18A) and 83 b (FIG. 13 shown inphantom) of rotating assembly 80 as described in more detail below. Inthe drawings and in the descriptions which follow, the term “proximal”,as is traditional, will refer to the end of the forceps 10 which iscloser to the user, while the term “distal” will refer to the end whichis further from the user.

[0080] As best seen in FIG. 1A, forceps 10 also includes an electricalinterface or plug 300 which connects the forceps 10 to a source ofelectrosurgical energy, e.g., a generator (not shown). Plug 300 includesa pair of prong members 302 a and 302 b which are dimensioned tomechanically and electrically connect the forceps 10 to the source ofelectrosurgical energy. An electrical cable 310 extends from the plug300 to a sleeve 99 which securely connects the cable 310 to the forceps10. As best seen in FIGS. 9, 11 and 18A, cable 310 is internally dividedinto cable lead 310 a and 310 b which each transmit electrosurgicalenergy through their respective feed paths through the forceps 10 to theend effector assembly 100 as explained in more detail below.

[0081] Handle assembly 30 includes a fixed handle 50 and a movablehandle 40. Fixed handle 50 is integrally associated with housing 20 andhandle 40 is movable relative to fixed handle 50 as explained in moredetail below with respect to the operation of the forceps 10. Rotatingassembly 80 is preferably attached to a distal end 303 (FIG. 18A) ofhousing 20 and is rotatable approximately 180 degrees in eitherdirection about a longitudinal axis “A”.

[0082] As best seen in FIGS. 2 and 13, housing 20 is formed from two (2)housing halves 20 a and 20 b which each include a plurality ofinterfaces 307 a, 307 b and 307 c (FIG. 13) which are dimensioned tomechanically align and engage one another to form housing 20 and enclosethe internal working components of forceps 10. As can be appreciated,fixed handle 50 which, as mentioned above is integrally associated withhousing 20, takes shape upon the assembly of the housing halves 20 a and20 b.

[0083] It is envisioned that a plurality of additional interfaces (notshown) may disposed at various points around the periphery of housinghalves 20 a and 20 b for ultrasonic welding purposes, e.g., energydirection/deflection points. It is also contemplated that housing halves20 a and 20 b (as well as the other components described below) may beassembled together in any fashion known in the art. For example,alignment pins, snap-like interfaces, tongue and groove interfaces,locking tabs, adhesive ports, etc. may all be utilized either alone orin combination for assembly purposes.

[0084] Likewise, rotating assembly 80 includes two halves 80 a and 80 bwhich, when assembled, enclose and engage the proximal end 16 of shaft12 to permit selective rotation of the end effector assembly 100 asneeded. Half 80 a includes a pair of detents 89 a (FIG. 13) which aredimensioned to engage a pair of corresponding sockets 89 b (shown inphantom in FIG. 13) disposed within half 80 b. Movable handle 40 andtrigger assembly 70 are preferably of unitary construction and areoperatively connected to the housing 20 and the fixed handle 50 duringthe assembly process.

[0085] As mentioned above, end effector assembly 100 is attached to thedistal end 14 of shaft 12 and includes a pair of opposing jaw members110 and 120. Movable handle 40 of handle assembly 30 is ultimatelyconnected to a drive rod 32 which, together, mechanically cooperate toimpart movement of the jaw members 110 and 120 from an open positionwherein the jaw members 110 and 120 are disposed in spaced relationrelative to one another, to a clamping or closed position wherein thejaw members 110 and 120 cooperate to grasp tissue 420 (FIG. 20)therebetween. This is explained in more detail below with respect toFIGS. 9-11 and 20-29.

[0086] It is envisioned that the forceps 10 may be designed such that itis fully or partially disposable depending upon a particular purpose orto achieve a particular result. For example, end effector assembly 100may be selectively and releasably engageable with the distal end 14 ofthe shaft 12 and/or the proximal end 16 of shaft 12 may be selectivelyand releasably engageable with the housing 20 and the handle assembly30. In either of these two instances, the forceps 10 would be considered“partially disposable” or “reposable”, i.e., a new or different endeffector assembly 100 (or end effector assembly 100 and shaft 12)selectively replaces the old end effector assembly 100 as needed.

[0087] Turning now to the more detailed features of the presentdisclosure as described with respect to FIGS. 1A-13, movable handle 40includes an aperture 42 defined therethrough which enables a user tograsp and move the handle 40 relative to the fixed handle 50. Handle 40also includes an ergonomically-enhanced gripping element 45 disposedalong the inner peripheral edge of aperture 42 which is designed tofacilitate gripping of the movable handle 40 during activation. It isenvisioned that gripping element 45 may include one or moreprotuberances, scallops and/or ribs 43 a, 43 b and 43 c, respectively,to facilitate gripping of handle 40. As best seen in FIG. 11, movablehandle 40 is selectively moveable about a pivot 69 from a first positionrelative to fixed handle 50 to a second position in closer proximity tothe fixed handle 50 which, as explained below, imparts movement of thejaw members 110 and 120 relative to one another.

[0088] As shown best in FIG. 11, housing 20 encloses a drive assembly 21which cooperates with the movable handle 40 to impart movement of thejaw members 110 and 120 from an open position wherein the jaw members110 and 120 are disposed in spaced relation relative to one another, toa clamping or closed position wherein the jaw members 110 and 120cooperate to grasp tissue therebetween. The handle assembly 30 cangenerally be characterized as a four-bar mechanical linkage composed ofthe following elements: movable handle 40, a link 65, a cam-like link 36and a base link embodied by fixed handle 50 and a pair of pivot points37 and 67 b. Movement of the handle 40 activates the four-bar linkagewhich, in turn, actuates the drive assembly 21 for imparting movement ofthe opposing jaw members 110 and 120 relative to one another to grasptissue therebetween. It is envisioned that employing a four-barmechanical linkage will enable the user to gain a significant mechanicaladvantage when compressing the jaw members 110 and 120 against thetissue 420 as explained in further detail below with respect theoperating parameters of the drive assembly 21. Although shown as afour-bar mechanical linkage, the present disclosure contemplates otherlinkages to effect relative motion of the jaw members 110 and 120 as isknown in the art.

[0089] Preferably, fixed handle 50 includes a channel 54 defined thereinwhich is dimensioned to receive a flange 92 which extends proximallyfrom movable handle 40. Preferably, flange 92 includes a fixed end 90which is affixed to movable handle 40 and a t-shaped free end 93 whichis dimensioned for facile reception within channel 54 of handle 50. Itis envisioned that flange 92 may be dimensioned to allow a user toselectively, progressively and/or incrementally move jaw members 110 and120 relative to one another from the open to closed positions. Forexample, it is also contemplated that flange 92 may include aratchet-like interface which lockingly engages the movable handle 40and, therefore, jaw members 110 and 120 at selective, incrementalpositions relative to one another depending upon a particular purpose.Other mechanisms may also be employed to control and/or limit themovement of handle 40 relative to handle 50 (and jaw members 110 and120) such as, e.g., hydraulic, semi-hydraulic, linear actuator(s),gas-assisted mechanisms and/or gearing systems.

[0090] As best illustrated in FIG. 11, housing halves 20 a and 20 b ofhousing 20, when assembled, form an internal cavity 52 which predefinesthe channel 54 within fixed handle 50 such that an entrance pathway 53and an exit pathway 58 are formed for reciprocation of the t-shapedflange end 93 therein. Once assembled, two generally triangular-shapedmembers 57 a and 57 b are positioned in close abutment relative to oneanother to define a rail or track 59 therebetween. During movement ofthe flange 92 along the entrance and exit pathways 53 and 58,respectively, the t-shaped end 93 rides along track 59 between the twotriangular members 57 a and 57 b according to the particular dimensionsof the triangularly-shaped members 57 a and 57 b, which, as can beappreciated, predetermines part of the overall pivoting motion of handle40 relative to fixed handle 50.

[0091] Once actuated, handle 40 moves in a generally arcuate fashiontowards fixed handle 50 about pivot 69 which causes link 65 to rotateproximally about pivots 67 a and 67 b which, in turn, cause cam-likelink 36 to rotate about pivots 37 and 69 in a generally proximaldirection. Movement of the cam-like link 36 imparts movement to thedrive assembly 21 as explained in more detail below. Moreover, proximalrotation of the link 65 about pivots 67 a and 67 b also causes a distalend 63 of link 65 to release, i.e., “unlock”, the trigger assembly 70for selective actuation. This feature is explained in detail withreference to FIGS. 21-29 and the operation of the knife assembly 200.

[0092] Turning now to FIG. 12 which shows an exploded view of the shaft12 and end effector assembly 100. As mentioned above, shaft 12 includesdistal and proximal ends 14 and 16, respectively. The distal end 14 isbifurcated and includes ends 14 a and 14 b which, together, define acavity 18 for receiving the end effector assembly 100. The proximal end16 includes a pair of notches 17 a (FIG. 29) and 17 b (FIG. 11) whichare dimensioned to engage corresponding detents 83 a and 83 b (FIG. 13)of the rotating assembly 80. As can be appreciated, actuation of therotation assembly 80 rotates the shaft 12 which, in turn, rotates theend effector assembly 100 to manipulate and grasp tissue 420.

[0093] Shaft 12 also includes a pair of longitudinally-oriented channels19 a (FIG. 15) and 19 b (FIG. 12) which are each dimensioned to carry anelectrosurgical cable lead 310 a and 310 b, respectively, therein forultimate connection to each jaw member 120 and 110, respectively, asexplained in more detail with reference to FIGS. 14-17 below. Shaft 12also includes a pair of longitudinally oriented slots 197 a and 197 bdisposed on ends 14 a and 14 b, respectively. Slots 197 a and 197 b arepreferable dimensioned to allow longitudinal reciprocation of a cam pin170 therein which, as explained below with reference to FIGS. 23 and 24,causes movement of the opposing jaw member 110 and 120 from the open toclosed positions.

[0094] Shaft 12 also includes a pair of sockets 169 a and 169 b disposedat distal ends 14 a and 14 b which are dimensioned to receive acorresponding pivot pin 160. As explained below, pivot pin 160 securesjaws 110 and 120 to the shaft 12 between bifurcated distal ends 14 a and14 b and mounts the jaw members 110 and 120 such that longitudinalreciprocation of the cam pin 170 rotates jaw members 110 and 120 aboutpivot pin 160 from the open to closed positions.

[0095] Shaft 12 is preferably dimensioned to slidingly receive a knifetube 34 therein which engages the knife assembly 200 such thatlongitudinal movement of the knife tube 34 actuates the knife assembly200 to divide tissue 420 as explained below with respect to FIGS. 29-31.Knife tube 34 includes a rim 35 located at a proximal end thereof and apair of opposing notches 230 a and 230 b (FIGS. 25 and 30) located at adistal end 229 thereof. As best shown in FIG. 13, rim 35 is dimensionedto engage a corresponding sleeve 78 disposed at a distal end of thetrigger assembly 70 such that distal movement of the sleeve 78translates the knife tube 34 which, in turn, actuates the knife assembly200. A seal 193 may be mounted atop the knife tube 34 and positionedbetween the knife tube 34 and the shaft 12. It is envisioned that theseal 193 may be dimensioned to facilitate reciprocation of the knifetube 34 within the shaft 12 and/or to protect the other, more sensitive,internal operating components of the forceps from undesirable fluidinundation during surgery. Seal 193 may also be employed tocontrol/regulate pneumo-peritoneal pressure leakage through forceps 10during surgery. Seal 193 preferably includes a pair of opposing bushings195 a and 195 b which assure consistent and accurate reciprocation ofthe knife tube 34 within shaft 12 (See FIG. 15).

[0096] Notches 230 a and 230 b are preferably dimensioned to engage acorresponding key-like interface 211 of the knife assembly 200 whichincludes a pair of opposing detents 212 a and 212 b and a pair ofopposing steps 214 a and 214 b. As best illustrated in FIGS. 25 and 30,each detent and step arrangement, e.g., 212 a and 214 a, respectively,securely engages a corresponding notch, e.g., 230 a, such that thedistal end of the step 214 a abuts the distal end 229 of the knife tube34. It is envisioned that engaging the knife tube 34 to the knifeassembly 200 in this manner will assure consistent and accurate distaltranslation of the knife tube 34 through the tissue 420.

[0097] As can be appreciated from the present disclosure, the knife tube34 and knife assembly 200 are preferably assembled to operateindependently from the operation of the drive assembly 21. However andas described in more detail below, knife assembly 200 is dependent onthe drive assembly 21 for activation purposes, i.e., theactivation/movement of the drive assembly 21 (via handle assembly 30 andthe internal working components thereof) “unlocks” the knife assembly200 for selective, separation of the tissue. For the purposes herein,the drive assembly 21 consists of both the drive rod 32 and thecompression mechanism 24 which includes a number of cooperative elementswhich are described below with reference to FIG. 13. It is envisionedthat arranging the drive assembly 21 in this fashion will enable facile,selective engagement of the drive rod 32 within the compressionmechanism 24 for assembly purposes.

[0098] Although the drawings depict a disposable version of thepresently disclosed forceps 10, it is contemplated that the housing 20may include a release mechanism (not shown) which enables selectivelyreplacement of the drive rod 32 for disposal purposes. In this fashion,the forceps will be considered “partially disposable” or “reposable”,i.e., the shaft 12, end effector assembly 100 and knife assembly 200 aredisposable and/or replaceable whereas the housing 20 and handle assembly30 are re-usable.

[0099] As best illustrated in FIGS. 16 and 17, drive rod 32 includes apair of chamfered or beveled edges 31 a and 31 b at a distal end thereofwhich are preferably dimensioned to allow facile reciprocation of thedrive rod 32 through a knife carrier or guide 220 which forms a part ofthe knife assembly 200. A pin slot 39 is disposed at the distal tip ofthe drive rod 32 and is dimensioned to house the cam pin 170 such thatlongitudinal reciprocation of the drive rod 32 within the knife tube 34translates the cam pin 170, which, in turn, rotates the jaw members 110and 120 about pivot pin 160. As will be explained in more detail belowwith respect to FIGS. 23 and 24, the cam pin 170 rides within slots 172and 174 of the jaw members 110 and 120, respectively, which causes thejaw members 110 and 120 to rotate from the open to closed positionsabout the tissue 420.

[0100] The proximal end of the drive rod 32 includes a tab 33 which ispreferably dimensioned to engage a corresponding compression sleeve 28disposed within the compression mechanism 24. Proximal movement of thesleeve 28 (as explained below with respect to FIGS. 21-24) reciprocates(i.e., pulls) the drive rod 32 which, in turn, pivots the jaw members110 and 120 from the open to closed positions. Drive rod 32 alsoincludes a donut-like spacer or o-ring 95 which is dimensioned tomaintain pneumo-peritoneal pressure during endoscopic procedures. It isalso envisioned that o-ring 95 may also prevent the inundation ofsurgical fluids which may prove detrimental to the internal operatingcomponents of the forceps 10. O-ring 95 is made also be made from amaterial having a low coefficient of friction to facilitate uniform andaccurate reciprocation of the drive rod 32 within the knife tube 34.

[0101] As mentioned above, the knife assembly 200 is disposed betweenopposing jaw members 110 and 120 of the end effector assembly 100.Preferably, the knife assembly 200 and the end effector assembly 100 areindependently operable, i.e., the trigger assembly 70 actuates the knifeassembly 200 and the handle assembly 30 actuates the end effectorassembly 100. Knife assembly 200 includes a bifurcated knife bar or rod210 having two forks 210 a and 210 b and a knife carrier or guide 220.Knife forks 210 a and 210 b include the above-described key-likeinterfaces 211 (composed of steps 214 a, 214 b and detents 212 a, 212 b,respectively) disposed at the proximal end thereof for engaging theknife tube 34 (as described above) and a common distal end 206 whichcarries a blade 205 thereon for severing tissue 420. Preferably, eachfork 210 a and 210 b includes a taper 213 a and 213 b, respectively,which converge to form common distal end 206. It is envisioned that thetapers 213 a and 213 b facilitate reciprocation of the knife blade 205through the end effector assembly 100 as described in more detail belowand as best illustrated in FIG. 30.

[0102] Each fork 210 a and 210 b also includes a tapered shoulderportion 221 a and 221 b disposed along the outer periphery thereof whichis dimensioned to engage a corresponding slot 223 a and 223 b,respectively, disposed in the knife carrier or guide 220 (See FIG. 16).It is envisioned that this shoulder portion 221 a, 221 b and slot 223 a,223 b arrangement may be designed to restrict and/or regulate theoverall distal movement of the blade 205 after activation. Each fork 210a and 210 b also includes an arcuately-shaped notch 215 a and 215 b,respectively disposed along the inward edge thereof which is dimensionedto facilitate insertion of a roller or bushing 216 disposed between thejaw members 110 and 120 during assembly.

[0103] As mentioned above, knife assembly 200 also includes a knifecarrier or guide 220 which includes opposing spring tabs 222 a and 222 bat a proximal end thereof and upper and lower knife guides 224 a and 224b, respectively, at the distal end thereof. The inner facing surface ofeach spring tab, e.g., 222 b, is preferably dimensioned to matinglyengage a corresponding chamfered edge, e.g., 31 b of the drive rod 32(FIG. 16) and the outer facing surface is preferably dimensioned forfriction-fit engagement with the inner periphery of the shaft 12. Asbest seen in FIG. 12, knife carrier 220 also includes a drive rodchannel 225 defined therethrough which is dimensioned to allowreciprocation of the drive rod 32 during the opening and closing of thejaw members 110 and 120. Knife guide 220 also includes rests 226 a and226 b which extend laterally therefrom which abut the proximal ends 132,134 of the jaw members 110 and 120 when disposed in the closed position.

[0104] Knife guides 224 a and 224 b preferably include slots 223 a and223 b, respectively, located therein which guide the knife forks 210 aand 210 b therealong during activation to provide consistent andaccurate reciprocation of the knife blade 205 through the tissue 420. Itis envisioned that slots 223 a and 223 b also restrict undesirablelateral movements of the knife assembly 200 during activation.Preferably, the knife carrier 220 is positioned at a point slightlybeyond the shoulder portions 221 a and 221 b when assembled.

[0105] The knife assembly 200 also includes a roller or bushing 216which is dimensioned to mate with the inner peripheral edge of each fork210 a and 210 b such that, during activation, the forks 210 a and 210 bglide over the roller or bushing 216 to assure facile and accuratereciprocation of the knife assembly 200 through the tissue 420. Bushing216 is also dimensioned to seat between opposing jaw members 110 and 120and is preferably secured therebetween by pivot pin 160. As mentionedabove, the arcuately-shaped notches 215 a and 215 b facilitate insertionof the bushing 216 during assembly.

[0106] The end effector assembly 100 includes opposing jaw members 110and 120 which are seated within cavity 18 defined between bifurcatedends 14 a and 14 b of shaft 12. Jaw members 110 and 120 are generallysymmetrical and include similar component features which cooperate topermit facile rotation about pivot pin 160 to effect the sealing anddividing of tissue 420. As a result and unless otherwise noted, only jawmember 110 and the operative features associated therewith are describein detail herein but as can be appreciated, many of these features applyto jaw member 120 as well.

[0107] More particularly, jaw member 110 includes a pivot flange 166which has an arcuately-shaped inner surface 167 which is dimensioned toallow rotation of jaw member 110 about bushing 216 and pivot pin 160upon reciprocation of drive rod 32 as described above. Pivot flange 166also includes a cam slot 172 which is dimensioned to engage cam pin 170such that longitudinal movement of the drive rod 32 causes the cam pin170 to ride along cam slot 172. It is envisioned that cam slot 172 maybe dimensioned to allow different rotational paths depending upon aparticular purpose or to achieve a particular result. For example,commonly assigned, co-pending U.S. application Ser. No. 09/177,950 whichis hereby incorporated by reference in its entirety herein, describes atwo-stage cam slot arrangement which, as can be appreciated, provides aunique rotational path for the jaw members about the pivot point.

[0108] Pivot flange 166 also includes a recess 165 which is preferablydimensioned to secure one free end of the bushing 216 between jawmembers 110 and 120. The inner periphery of recess 165 is preferablydimensioned to receive pivot pin 160 therethrough to secure the jawmember 110 to the shaft 12. Jaw member 120 includes a similar recess 175(FIG. 14) which secures the opposite end of bushing 216 and jaw member120 to shaft 12.

[0109] Jaw member 110 also includes a jaw housing 116, an insulativesubstrate or insulator 114 and an electrically conducive surface 112.Jaw housing 116 includes a groove (not shown—See groove 179 of jawmember 120) defined therein which is dimensioned to engage a ridge-likeinterface 161 disposed along the outer periphery of insulator 114.Insulator 114 is preferably dimensioned to securely engage theelectrically conductive sealing surface 112. This may be accomplished bystamping, by overmolding, by overmolding a stamped electricallyconductive sealing plate and/or by overmolding a metal injection moldedseal plate.

[0110] All of these manufacturing techniques produce an electrode havingan electrically conductive surface 112 which is substantially surroundedby an insulating substrate 114. The insulator 114, electricallyconductive sealing surface 112 and the outer, non-conductive jaw housing116 are preferably dimensioned to limit and/or reduce many of the knownundesirable effects related to tissue sealing, e.g., flashover, thermalspread and stray current dissipation. Alternatively, it is alsoenvisioned that the jaw members 110 and 120 may be manufactured from aceramic-like material and the electrically conductive surface(s) 112 arecoated onto the ceramic-like jaw members 110 and 120.

[0111] Preferably, the electrically conductive sealing surface 112 mayalso include a pinch trim 119 (FIG. 25) which facilitates secureengagement of the electrically conductive surface 112 to the insulatingsubstrate 114 and also simplifies the overall manufacturing process. Itis envisioned that the electrically conductive sealing surface 112 mayalso include an outer peripheral edge which has a radius and theinsulator 114 meets the electrically conductive sealing surface 112along an adjoining edge which is generally tangential to the radiusand/or meets along the radius. Preferably, at the interface, theelectrically conductive surface 112 is raised relative to the insulator114. These and other envisioned embodiments are discussed inconcurrently-filed, co-pending, commonly assigned Application Serial No.PCT/US01/11412 entitled “ELECTROSURGICAL INSTRUMENT WHICH REDUCESCOLLATERAL DAMAGE TO ADJACENT TISSUE” by Johnson et al. andconcurrently-filed, co-pending, commonly assigned Application Serial No.PCT/US01/11411 entitled “ELECTROSURGICAL INSTRUMENT WHICH IS DESIGNED TOREDUCE THE INCIDENCE OF FLASHOVER” by Johnson et al.

[0112] Insulator 114 also includes an inwardly facing finger 162 whichabuts pivot flange 166 and is designed to restrict/reduce proximaltissue spread and/or isolate the electrically conductive sealing surface112 from the remaining end effector assembly 100 during activation.Preferably, the electrically conductive surface 112 and the insulator114, when assembled, form a longitudinally-oriented channel 168 a, 168 bdefined therethrough for reciprocation of the knife blade 205. Moreparticularly, and as best illustrated in FIG. 14, insulator 114 includesa first channel 168 b which aligns with a second channel 168 a onelectrically conductive sealing surface 112 to form the complete knifechannel. It is envisioned that the knife channel 168 a, 168 bfacilitates longitudinal reciprocation of the knife blade 205 along apreferred cutting plane “B-B” to effectively and accurately separate thetissue 420 along the formed tissue seal 425 (See FIGS. 27, 28 and 31.

[0113] As mentioned above, jaw member 120 include similar elements whichinclude: a pivot flange 176 which has an arcuately-shaped inner surface177, a cam slot 174, and a recess 175; a jaw housing 126 which includesa groove 179 which is dimensioned to engage a ridge-like interface 171disposed along the outer periphery of an insulator 124; the insulator124 which includes an inwardly facing finger 172 which abuts pivotflange 176; and an electrically conducive sealing surface 122 which isdimensioned to securely engage the insulator 124. Likewise, theelectrically conductive surface 122 and the insulator 124, whenassembled, form a longitudinally-oriented channel 178 a, 178 b definedtherethrough for reciprocation of the knife blade 205.

[0114] Preferably, the jaw members 110 and 120 are electrically isolatedfrom one another such that electrosurgical energy can be effectivelytransferred through the tissue 420 to form seal 425. For example and asbest illustrated in FIGS. 14 and 15, each jaw member, e.g., 110,includes a uniquely-designed electrosurgical cable path disposedtherethrough which transmits electrosurgical energy to the electricallyconductive sealing surfaces 112, 122. More particularly, jaw member 110includes a cable guide 181 a disposed atop pivot flange 166 whichdirects cable lead 310 a towards an aperture 188 disposed through jawhousing 116. Aperture 188, in turn, directs cable lead 310 a towardselectrically conductive sealing surface 112 through a window 182disposed within insulator 114. A second cable guide 181 b secures cablelead 310 a along the predefined cable path through window 182 anddirects a terminal end 310 a ′ of the cable lead 310 a into crimp-likeelectrical connector 183 disposed on an opposite side of theelectrically conductive sealing surface 112. Preferably, cable lead 310a is held loosely but securely along the cable path to permit rotationof the jaw member 110 about pivot 169.

[0115] As can be appreciated, this isolates electrically conductivesealing surface 112 from the remaining operative components of the endeffector assembly 100 and shaft 12. Jaw member 120 includes a similarcable path disposed therein and therethrough which includes similarlydimensioned cable guides, apertures and electrical connectors which arenot shown in the accompanying illustrations.

[0116] FIGS. 15-17 also show the presently disclosed feed path for bothelectrosurgical cable leads 310 a and 310 b along the outer periphery ofthe shaft 12 and through each jaw member 110 and 120. More particularly,FIG. 15 shows a cross section of the electrosurgical cable leads 310 aand 310 b disposed within channels 19 a and 19 b, respectively, alongshaft 12. FIGS. 16 and 17 show the feed path of the cable leads 310 aand 310 b from the opposite channels 19 a and 19 b of the shaft 12through the pivot flanges 166 and 176 of the jaw members 110 and 120,respectively. It is contemplated that this unique cable feed path forcable leads 310 a and 310 b from the shaft 12 to the jaw members 110 and120 not only electrically isolates each jaw member 100 and 120 but alsoallows the jaw members 110 and 120 to pivot about pivot pin 160 withoutunduly straining or possibly tangling the cable leads 310 a and 310 b.Moreover, it is envisioned that the crimp-like electrical connector 183(and the corresponding connector in jaw member 120) greatly facilitatesthe manufacturing and assembly process and assures a consistent andtight electrical connection for the transfer of energy through thetissue 420. As best shown in FIG. 17, the outer surface of shaft 12 maybe covered by heat shrink tubing 500 or the like which protects thecable leads 310 a and 310 b from undue wear and tear and secures cableleads 310 a and 310 b within their respective channels 19 a and 19 b.

[0117]FIGS. 18A and 18B show the feed path of the cable leads 310 a and310 b through the rotating assembly 80 which, again, allows the useradded flexibility during the use of the forceps 10 due to the uniquenessof the feed path. More particularly, FIG. 18A shows the feed path ofcable lead 310 a through half 80 a of the rotating assembly 80 and FIG.18B shows the path of cable leads 310 a and 310 b as the cable leads 310a and 310 b feed through the instrument housing 20 a, through half 80 aof the rotating assembly 80 and to the channels 19 a and 19 b of theshaft 12. FIG. 18A only shows the feed path of cable lead 310 a throughhalf 80 a of the rotating assembly 80, however, as can be appreciated,cable lead 310 b (shown broken in FIG. 19) is positioned in a similarfashion within half 80 b of rotating assembly 80.

[0118] As best illustrated in FIG. 18A, it is envisioned that cableleads 310 a and 310 b are fed through respective halves 80 a and 80 b ofthe rotating assembly 80 in such a manner to allow rotation of the shaft12 (via rotation of the rotating assembly 80) in the clockwise orcounter-clockwise direction without unduly tangling or twisting thecable leads 310 a and 310 b. More particularly, each cable lead, e.g.,310 a, is looped through each half 80 a of the rotating assembly 80 toform slack-loops 321 a and 321 b which traverse either side oflongitudinal axis “A”. Slack-loop 321 a redirects cable lead 310 aacross one side of axis “A” and slack-loop 321 b returns cable lead 310a across axis “A”. It is envisioned that feeding the cable leads 310 aand 310 b through the rotating assembly 80 in this fashion allows theuser to rotate the shaft 12 and the end effector assembly 100 withoutunduly straining or tangling the cable leads 310 a and 310 b which mayprove detrimental to effective sealing. Preferably, this loop-like cablefeed path allows the user to rotate the end effector assembly 100 about180 degrees in either direction without straining the cable leads 310 aand 310 b. The presently disclosed cable lead feed path is envisioned torotate the cable leads 310 a and 310 b approximately 178 degrees ineither direction.

[0119]FIG. 19 shows an internal view of half 80 a of the rotatingassembly 80 as viewed along axis “A” to highlight the internal featuresthereof. More particularly, at least one stop 88 is preferablypositioned within each rotating half 80 a and 80 b which operates tocontrol the overall rotational movement of the rotating assembly 80 toabout 180 degree in either direction. The stop member 88 is dimensionedto interface with a corresponding notch 309 c disposed along theperiphery of outer flange 309 to prevent unintended over-rotation of therotating assembly 80 which may unduly strain one or both of the cableleads 310 a and 310 b.

[0120]FIG. 18B shows the feed path of the electrical cable leads 310 aand 310 b from the housing 20 a, through the rotating assembly 80 and tothe shaft 12. It is envisioned that the cable leads 310 a and 310 b aredirected through each part of the forceps 10 via a series of cable guidemembers 311 a-311 g disposed at various positions through the housing 20and rotating assembly 80. As explained below, a series of mechanicalinterfaces, e.g., 309 a, 309 b (FIG. 13) and 323 a, 323 b (FIG. 13) mayalso be dimensioned to contribute in guiding cables 310 a and 310 bthrough the housing 20 and rotating assembly 80.

[0121] Turning back to FIG. 13 which shows the exploded view of thehousing 20, rotating assembly 80, trigger assembly 70 and handleassembly 30, it is envisioned that all of these various component partsalong with the shaft 12 and the end effector assembly 100 are assembledduring the manufacturing process to form a partially and/or fullydisposable forceps 10. For example and as mentioned above, the shaft 12and/or end effector assembly 100 may be disposable and, therefore,selectively/releasably engagable with the housing 20 and rotatingassembly 80 to form a partially disposable forceps 10 and/or the entireforceps 10 may be disposable after use.

[0122] Housing 20 is preferably formed from two housing halves 20 a and20 b which engage one another via a series of mechanical interfaces 307a, 307 b, 307 c and 308 a, 308 b, 308 c respectively, to form aninternal cavity 300 for housing the hereindescribed internal workingcomponents of the forceps 10. For the purposes herein, housing halves 20a and 20 are generally symmetrical and, unless otherwise noted, acomponent described with respect to housing half 20 a will have asimilar component which forms a part of housing half 20 b.

[0123] Housing half 20 a includes proximal and distal ends 301 a and 303a, respectively. Proximal end 301 a is preferably dimensioned to receivean electrical sleeve 99 which secures the electrosurgical cable 310(FIG. 1) within the housing 20. As best shown in FIGS. 9 and 21, pairedcable 310 splits into two electrosurgical cable leads 310 a and 310 bwhich are subsequently fed through the housing 20 to ultimately transmitdifferent electrical potentials to the opposing jaw members 110 and 120.As mentioned above, various cable guides 311 a-311 g are positionedthroughout the housing 20 and the rotating assembly 80 to direct thecable leads 310 a and 310 b to the channels 19 a and 19 b disposed alongthe outer periphery of the shaft 12.

[0124] The distal end 303 a is generally arcuate in shape such that,when assembled, distal ends 303 a and 303 b form a collar 303 (FIG. 13)which extends distally from the housing 20. Each distal end 303 a, 303 bof the collar 303 includes an outer flange 309 a, 309 b and a recess 323a, 323 b which cooperate to engage corresponding mechanical shoulders 84a, 84 b (FIG. 29) and flanges 87 a, 87 b, respectively, disposed withinthe rotating assembly 80. As can be appreciated, the interlockingengagement of the flanges 309 a, 309 b with the shoulders 84 a, 84 b andthe recesses 323 a, 323 b with the flanges 87 a, 87 b are dimensioned toallow free rotation about of the rotating assembly 80 about collar 303when assembled. As mentioned above, the stop member(s) 88 and thenotch(es) mechanically cooperate to limit rotational movement of therotating assembly 80 to avoid straining cable leads 310 a and 310 b.

[0125] Each distal end 303 a, 303 b of collar 303 also includes an innercavity 317 a and 317 b (FIGS. 9 and 21), respectively, defined thereinwhich is dimensioned to permit free rotation of the shaft 12, knife tube34 and cable leads 310 a and 310 b housed therein. A plurality ofdetents 89 a located within rotating assembly 80 engage a correspondingplurality of sockets 89 b (FIG. 13) disposed within rotating half 80 bto poise the rotating assembly 80 in rotational relationship atop collar303.

[0126] Housing half 20 a also includes a plurality of hub-like pivotmounts 329 a, 331 a and 333 a which as explained in more detail belowwith respect to the operation of the instrument, cooperate with oppositehub-like pivot mounts (shown in phantom in FIG. 13) disposed on housinghalf 20 b to engage the free ends of pivot pins 37, 67 b and 77,respectively, which are associated with the different operatingcomponents described below. Preferably, each of these mounts 329 a, 331a and 333 a provide a fixed point of rotation for each pivoting element,namely, cam link 36, handle link 65 and trigger assembly 70,respectively.

[0127] As best seen in FIGS. 11 and 13, fixed handle 50 which takesshape upon the assembly of housing 20 includes a scallop-like outersurface 51 and an internal cavity 52 defined therein. As mentioned abovewith respect to the discussion of FIG. 11, these elements and the otherinternal elements of the fixed handle 50 cooperate with movable handle40 to activates the four-bar mechanical linkage which, in turn, actuatesthe drive assembly 21 for imparting movement of the opposing jaw members110 and 120 relative to one another to grasp tissue 420 therebetween.

[0128] The handle assembly 30 which includes the above-mentioned fixedhandle 50 and movable handle 40 also includes the cam link 36 which isgenerally triangular in shape. The cam link includes an upper piston 38,a fixed pivot 37 and a handle pivot 69. Cam link is assembled within theinternal cavity 300 of housing 20 between housing halves 20 a and 20 b.More particularly, fixed pivot 37 is rotatingly mounted within fixedmounts 329 a and 329 b between opposing housing halves 20 a and 20 b andthe handle pivot 69 is rotatingly mounted within the bifurcated end ofhandle 40 through apertures 68 a and 68 b. Cam piston 38 is poisedwithin a longitudinal channel 25 c defined through the drive assembly 70(explained in further detail below with respect to the discussion of thedrive assembly 70) in abutting relationship with a compression tab 25such that movement of the handle 40 rotates piston 38 proximally againstcoil spring 22. These and the other details relating to the operationalfeatures are discussed below with reference to FIGS. 21-29.

[0129] Link 65 is also associated with the handle assembly 30 and formsan integral part of the four-bar mechanical linkage. Link 65 includes adistal end 63 and two pivot pins 67 a and 67 b. Pivot pin 67 a engagesapertures 68 a and 68 b disposed within the movable handle 40 and pivot67 b engages fixed mounts 331 a and 331 b between housing halves 20 aand 20 b such that movement of the handle 40 towards fixed handle 50pivots link 65 about pivots 67 a and 67 b. As explained in more detailbelow, distal end 63 acts as a lockout for the trigger assembly 70.

[0130] Movable handle 40 includes a flange 92 which is preferablymounted to the movable handle 40 by pins 46 a and 46 b which engageapertures 41 a and 41 b disposed within handle 40 and apertures 91 a and91 b disposed within flange 92, respectively. Other methods ofengagement are also contemplated, snap-lock, spring tab, etc. Flange 92also includes a t-shaped distal end 93 which, as mentioned above withrespect to FIG. 11, rides within a predefined channel 54 disposed withinfixed handle 50. Additional features with respect to the t-shaped end 93are explained below in the detailed discussion of the operationalfeatures of the forceps 10.

[0131] A drive assembly 21 is preferably positioned within the housing20 between housing halves 20 a and 20 b. As discussed above, the driveassembly 21 includes the previously described drive rod 32 and thecompression mechanism 24. Compression mechanism 24 includes acompression sleeve 27 which is telescopically and/or slidingly disposedwithin a spring mount 26. The distal end 28 of the compression sleeve 27is preferably C-shaped and dimensioned to engage the tab 33 disposed atthe proximal end of drive rod 32 such that longitudinal movement of thecompression sleeve 27 actuates the drive rod 32. The proximal end of thecompression sleeve 27 is dimensioned to engage a barbell-shapedcompression tab 25 which is disposed within a longitudinal slot 25 s ofthe spring mount 26. The compression sleeve 27 also includes alongitudinal slot or channel 25 c which is longitudinally aligned withslot 25 s and is dimensioned to receive the cam piston 38 of the camlink 36 described above.

[0132] The proximal end of spring mount 26 includes a circular flange 23which is dimensioned to bias the compression spring 22 once thecompression mechanism 24 is assembled and seated within housing 20 (FIG.11). The distal end of spring mount 26 includes a flange 25 f whichrestricts distal movement of the tab 25 to within the slot 25 s of thespring mount 26 and biases the opposite end the spring 22.

[0133] As best seen in FIG. 11, once assembled, spring 22 is poised forcompression atop spring mount 26 upon actuation of the handle assembly30. More particularly, movement of the cam piston 38 within slot 25 c(via movement of handle assembly 30) moves the tab 25 atop slot 25 s andreciprocates the compression sleeve 27 within the spring mount 26 tocompress the spring 22. Proximal movement of the compression sleeve 27imparts proximal movement to the drive rod 32 which closes jaw members110 and 120 about tissue 420 (FIG. 26). Compression of the spring 22 maybe viewed through one or more windows 340 disposed within the housinghalves, e.g., 20 b.

[0134]FIG. 13 also shows the trigger assembly 70 which activates theknife assembly 200 as described above with respect to FIG. 12. Moreparticularly, trigger assembly 70 includes an actuator 73 having acuff-like distal end 78 which is dimensioned to receive the proximal rim35 of the knife tube 34. A drive pin 74 extends laterally from theproximal end of actuator 73. Trigger assembly 70 also includes anergonomically enhanced finger tab 72 having opposing wing-like flanges72 a and 72 b which are envisioned to facilitate gripping and firing ofthe trigger assembly during surgery.

[0135] As best shown in FIG. 11, the compression sleeve 27 isdimensioned to slide internally within actuator 73 when the forceps 10is assembled. Likewise, the actuator 73, when activated, can slidedistally along the outer periphery of compression sleeve 27 to actuatethe knife assembly 200 as described above with respect to FIG. 12. Thedrive pin 74 is dimensioned to ride along a pair of guide rails 71 a and71 b disposed within a bifurcated tail portion of finger tab 72 whichincludes ends 76 a and 76 b, respectively.

[0136] A hinge or pivot pin 77 mounts the finger tab 72 between housinghalves 20 a and 20 within mounts 333 a and 333 b. A torsion spring 75may also be incorporated within the trigger assembly 70 to facilitateprogressive and consistent longitudinal reciprocation of the actuator 73and knife tube 34 to assure reliable separation along the tissue seal425 (FIGS. 27 and 28). In other words, the trigger assembly 70 isconfigured in a proximal, “pre-loaded” configuration prior toactivation. This assures accurate and intentional reciprocation of theknife assembly 200. Moreover, it is envisioned that the “pre-load”configuration of the torsion spring 75 acts as an automatic recoil ofthe knife assembly 200 to permit repeated reciprocation through thetissue as needed. As mentioned above, a plurality of gripping elements71 is preferably incorporated atop the finger tab 72 and wing flanges 72a and 72 b to enhance gripping of the finger tab 72.

[0137] Preferably, the trigger assembly 70 is initially prevented fromfiring due to the unique configuration of the distal end 63 of the link65 which abuts against the finger tab 72 and “locks” the triggerassembly 70 prior to actuation of the handle assembly 30. Moreover, itis envisioned that the opposing jaw members 110 and 120 may be rotatedand partially opened and closed without unlocking the trigger assembly70 which, as can be appreciated, allows the user to grip and manipulatethe tissue 420 without premature activation of the knife assembly 200.As mentioned below, only when the t-shaped end 93 of flange 92 iscompletely reciprocated within channel 54 and seated within apre-defined catch basin 62 (explained below) will the distal end 63 oflink 65 move into a position which will allow activation of the triggerassembly 70.

[0138] The operating features and relative movements of the internalworking components of the forceps 10 are shown by phantom representationand directional arrows and are best illustrated in FIGS. 21-29. Asmentioned above, when the forceps 10 is assembled a predefined channel54 is formed within the cavity 52 of fixed handle 50. The channel 54includes entrance pathway 53 and an exit pathway 58 for reciprocation ofthe flange 92 and the t-shaped end 93 therein. Once assembled, the twogenerally triangular-shaped members 57 a and 57 b are positioned inclose abutment relative to one another and define track 59 disposedtherebetween.

[0139] More particularly, FIGS. 21 and 22 show the initial actuation ofhandle 40 towards fixed handle 50 which causes the free end 93 of flange92 to move generally proximally and upwardly along entrance pathway 53.During movement of the flange 92 along the entrance and exit pathways 53and 58, respectively, the t-shaped end 93 rides along track 59 betweenthe two triangular members 57 a and 57 b.

[0140] As the handle 40 is squeezed and flange 92 is incorporated intochannel 54 of fixed handle 50, the cam link 36, through the mechanicaladvantage of the four-bar mechanical linkage, is rotated generallyproximally about pivots 37 and 69 such that the cam piston 38 biases tab25 which compresses spring 22 against flange 23 of the spring mount(FIG. 23). Simultaneously, the drive rod 32 is pulled proximally by thecompression sleeve 27 which, in turn, causes cam pin 170 to moveproximally within cam slots 172 and 174 and close the jaw members 110and 120 relative to one another (FIG. 24). It is envisioned that channel197 may be dimensioned slightly larger than needed to take into accountany dimensional inconsistencies with respect to manufacturing tolerancesof the various operating components of the end effector assembly 100(FIG. 24)

[0141] It is envisioned that the utilization of a four-bar linkage willenable the user to selectively compress the coil spring 22 a specificdistance which, in turn, imparts a specific load on the drive rod 32.The drive rod 32 load is converted to a torque about the jaw pivot 160by way of cam pin 170. As a result, a specific closure force can betransmitted to the opposing jaw members 110 and 120. It is alsocontemplated, that window 340 disposed in the housing 20 may includegraduations, visual markings or other indicia which provide feedback tothe user during compression of the handle assembly 30. As can beappreciated, the user can thus selectively regulate the progressiveclosure forces applied to the tissue 420 to accomplish a particularpurpose or achieve a particular result. For example, it is envisionedthat the user may progressively open and close the jaw members 110 and120 about the tissue without locking the flange 93 in the catch basin62. The window 340 may include a specific visual indicator which relatesto the proximal-most position of flange 93 prior to engagement withinthe catch basin 62.

[0142] As mentioned above, the jaw members 110 and 120 may be opened,closed and rotated to manipulate tissue 420 until sealing is desiredwithout unlocking the trigger assembly 70. This enables the user toposition and re-position the forceps 10 prior to activation and sealing.More particularly, as illustrated in FIG. 4, the end effector assembly100 is rotatable about longitudinal axis “A” through rotation of therotating assembly 80. As mentioned above, it is envisioned that theunique feed path of the cable leads 310 a and 310 b through the rotatingassembly 80, along shaft 12 and, ultimately, through the jaw members 110and 120 enable the user to rotate the end effector assembly 100 about180 degrees in both the clockwise and counterclockwise direction withouttangling or causing undue strain on the cable leads 310 a and 310 b. Ascan be appreciated, this facilitates the grasping and manipulation oftissue 420.

[0143] A series of stop members 150 a-150 f are preferably employed onthe inner facing surfaces of the electrically conductive sealingsurfaces 112 and 122 to facilitate gripping and manipulation of tissueand to define a gap “G” (FIG. 24) between opposing jaw members 110 and120 during sealing and cutting of tissue. A detailed discussion of theseand other envisioned stop members 150 a-150 f as well as variousmanufacturing and assembling processes for attaching and/or affixing thestop members 150 a-150 f to the electrically conductive sealing surfaces112, 122 are described in commonly-assigned, co-pending U.S. ApplicationSerial No. PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITHNON-CONDUCTIVE STOP MEMBERS” by Dycus et al. which is herebyincorporated by reference in its entirety herein.

[0144] Once the desired position for the sealing site 425 is determinedand the jaw members 110 and 120 are properly positioned, handle 40 maybe compressed fully such that the t-shaped end 93 of flange 92 clears apredefined rail edge 61 located atop the triangular-shaped members 57 aand 57 b. Once end 93 clears edge 61, distal movement of the handle 40and flange 92, i.e., release, is redirected by edge 61 into a catchbasin 62 located within the exit pathway 58. More particularly, upon aslight reduction in the closing pressure of handle 40 against handle 50,the handle 40 returns slightly distally towards entrance pathway 53 butis re-directed towards exit pathway 58. At this point, the release orreturn pressure between the handles 40 and 50 which is attributable anddirectly proportional to the release pressure associated with thecompression of the drive assembly 70 causes the end 93 of flange 92 tosettle or lock within catch basin 62. Handle 40 is now secured inposition within fixed handle 50 which, in turn, locks the jaw members110 and 120 in a closed position against the tissue 420.

[0145] At this point the jaws members 100 and 120 are fully compressedabout the tissue 420 (FIG. 26). Moreover, the forceps 10 is now readyfor selective application of electrosurgical energy and subsequentseparation of the tissue 420, i.e., as t-shaped end 93 seats withincatch basin 62, link 65 moves into a position to permit activation ofthe trigger assembly 70 (FIGS. 21 and 29).

[0146] As the t-shaped end 93 of flange 92 becomes seated within catchbasin 62, a proportional axial force on the drive rod 32 is maintainedwhich, in turn, maintains a compressive force between opposing jawmembers 110 and 120 against the tissue 420. It is envisioned that theend effector assembly 100 and/or the jaw members 110 and 120 may bedimensioned to off-load some of the excessive clamping forces to preventmechanical failure of certain internal operating elements of the endeffector 100.

[0147] As can be appreciated, the combination of the four-bar mechanicaladvantage along with the compressive force associated with thecompression spring 22 facilitate and assure consistent, uniform andaccurate closure pressure about the tissue 420.

[0148] By controlling the intensity, frequency and duration of theelectrosurgical energy applied to the tissue 420, the user can eithercauterize, coagulate/desiccate, seal and/or simply reduce or slowbleeding. As mentioned above, two mechanical factors play an importantrole in determining the resulting thickness of the sealed tissue andeffectiveness of the seal 425, i.e., the pressure applied betweenopposing jaw members 110 and 120 and the gap distance “G” between theopposing sealing surfaces 112, 122 of the jaw members 110 and 120 duringthe sealing process. However, thickness of the resulting tissue seal 425cannot be adequately controlled by force alone. In other words, too muchforce and the two jaw members 110 and 120 would touch and possibly shortresulting in little energy traveling through the tissue 420 thusresulting in a bad tissue seal 425. Too little force and the seal 425would be too thick.

[0149] Applying the correct force is also important for other reasons:to oppose the walls of the vessel; to reduce the tissue impedance to alow enough value that allows enough current through the tissue 420; andto overcome the forces of expansion during tissue heating in addition tocontributing towards creating the required end tissue thickness which isan indication of a good seal 425.

[0150] Preferably, the electrically conductive sealing surfaces 112, 122of the jaw members 110, 120, respectively, are relatively flat to avoidcurrent concentrations at sharp edges and to avoid arcing between highpoints. In addition and due to the reaction force of the tissue 420 whenengaged, jaw members 110 and 120 are preferably manufactured to resistbending. For example, the jaw members 110 and 120 may be tapered alongthe width thereof which is advantageous for two reasons: 1) the taperwill apply constant pressure for a constant tissue thickness atparallel; 2) the thicker proximal portion of the jaw members 110 and 120will resist bending due to the reaction force of the tissue 420.

[0151] It is also envisioned that the jaw members 110 and 120 may becurved in order to reach specific anatomical structures. For example, itis contemplated that dimensioning the jaw members 110 and 120 at anangle of about 50 degrees to about 70 degrees is preferred for accessingand sealing specific anatomical structures relevant to prostatectomiesand cystectomies, e.g., the dorsal vein complex and the lateralpedicles. It is also envisioned that the knife assembly 200 (or one ormore of the components thereof) may be made from a semi-compliantmaterial or may be multi-segmented to assure consistent, facile andaccurate cutting through the above envisioned curved jaw member 110 and120.

[0152] As mentioned above, at least one jaw member, e.g., 110 mayinclude a stop member, e.g., 150 a, which limits the movement of the twoopposing jaw members 110 and 120 relative to one another (FIGS. 6 and7). Preferably, the stop member, e.g., 150 a, extends from the sealingsurface 112, 122 a predetermined distance according to the specificmaterial properties (e.g., compressive strength, thermal expansion,etc.) to yield a consistent and accurate gap distance “G” during sealing(FIG. 24). Preferably, the gap distance between opposing sealingsurfaces 112 and 122 during sealing ranges from about 0.001 inches toabout 0.005 inches and, more preferably, between about 0.002 and about0.003 inches.

[0153] Preferably, stop members 150 a-150 f are made from an insulativematerial, e.g., parylene, nylon and/or ceramic and are dimensioned tolimit opposing movement of the jaw members 110 and 120 to within theabove mentioned gap range. It is envisioned that the stop members 150a-150 f may be disposed one or both of the jaw members 110 and 120depending upon a particular purpose or to achieve a particular result.Many different configurations for the stop members 150 a-150 f arediscussed in detail in commonly-assigned, copending U.S. ApplicationSerial No. PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITHNON-CONDUCTIVE STOP MEMBERS” by Dycus et al. which is herebyincorporated by reference in its entirety herein.

[0154] One particular stop member configuration is shown in FIG. 33which shows a single, circular stop member 150 d disposed on either sideof the knife channel 178 a near the proximal-most portion of one of thesealing surfaces, e.g., 112. Two sets of circular stop member pairs 150e are disposed in the middle portion of sealing surface 112 on eitherside of the knife channel 178 a and a single, circular stop member 150 fis disposed at the distal-most portion of sealing surface 112 on eitherside of the knife channel 178 a. It is envisioned any of the variousstop member configurations contemplated herein may be disposed on one orboth sealing surfaces 112, 122 depending upon a particular purpose or toachieve a particular result. Moreover, it is envisioned that the stopmembers 150 a-150 f may be disposed on one side of the knife channel 178a according to a specific purpose.

[0155] Preferably, the non-conductive stop members 150 a-150 f aremolded onto the jaw members 110 and 120 (e.g., overmolding, injectionmolding, etc.), stamped onto the jaw members 110 and 120 or deposited(e.g., deposition) onto the jaw members 110 and 120. For example, onetechnique involves thermally spraying a ceramic material onto thesurface of the jaw member 110 and 120 to form the stop members 150 a-150f. Several thermal spraying techniques are contemplated which involvedepositing a broad range of heat resistant and insulative materials onvarious surfaces to create stop members for controlling the gap distancebetween electrically conductive surfaces 112, 122. Other techniques fordisposing the stop members 150 a-150 f on the electrically conductivesurfaces 112 and 122 are also contemplated, e.g., slide-on, snap-on,adhesives, molds, etc.

[0156] Further, although it is preferable that the stop members 150a-150 f protrude about 0.001 inches to about 0.005 inches and preferablyabout 0.002 inches to about 0.003 inches from the inner-facing surfaces112, 122 of the jaw member 110 and 120, in some cases it may bepreferable to have the stop members 150 a-150 f protrude more or lessdepending upon a particular purpose. For example, it is contemplatedthat the type of material used for the stop members 150 a-150 f and thatmaterial's ability to absorb the large compressive closure forcesbetween jaw members 110 and 120 will vary and, therefore, the overalldimensions of the stop members 150 a-150 f may vary as well to producethe desired gap distance “G”.

[0157] In other words, the compressive strength of the material alongwith the desired or ultimate gap distance “G” required (desirable) foreffective sealing are parameters which are carefully considered whenforming the stop members 150 a-150 f and one material may have to bedimensioned differently from another material to achieve the same gapdistance or desired result. For example, the compressive strength ofnylon is different from ceramic and, therefore, the nylon material mayhave to be dimensioned differently, e.g., thicker, to counteract theclosing force of the opposing jaw members 110 and 120 and to achieve thesame desired gap distance “G”′ when utilizing a ceramic stop member.

[0158] As best shown in FIGS. 27 and 28, as energy is being selectivelytransferred to the end effector assembly 100, across the jaw members 110and 120 and through the tissue 420, a tissue seal 425 forms isolatingtwo tissue halves 420 a and 420 b. At this point and with other knownvessel sealing instruments, the user must remove and replace the forceps10 with a cutting instrument (not shown) to divide the tissue halves 420a and 420 b along the tissue seal 425. As can be appreciated, this isboth time consuming and tedious and may result in inaccurate tissuedivision across the tissue seal 425 due to misalignment or misplacementof the cutting instrument along the ideal tissue cutting plane “B-B”.

[0159] As explained in detail above, the present disclosure incorporatesa knife assembly 200 which, when activated via the trigger assembly 70,progressively and selectively divides the tissue 420 along the idealtissue plane “B-B” in an accurate and precise manner to effectively andreliably divide the tissue 420 into two sealed halves 420 a and 420 b(FIG. 31) with a tissue gap 430 therebetween. The reciprocating knifeassembly 200 allows the user to quickly separate the tissue 420immediately after sealing without substituting a cutting instrumentthrough a cannula or trocar port 410. As can be appreciated, accuratesealing and dividing of tissue 420 is accomplished with the sameforceps. It is envisioned that knife blade 205 may also be coupled tothe same or an alternative electrosurgical energy source to facilitateseparation of the tissue 420 along the tissue seal 425 (Not shown).

[0160] Moreover, it is envisioned that the angle of the blade tip 207 ofthe knife blade 205 may be dimensioned to provide more or lessaggressive cutting angles depending upon a particular purpose. Forexample, the blade tip 207 may be positioned at an angle which reduces“tissue wisps” associated with cutting. More over, the blade tip 207 maybe designed having different blade geometries such as serrated, notched,perforated, hollow, concave, convex etc. depending upon a particularpurpose or to achieve a particular result.

[0161] Although it is envisioned that the blade tip 207 have arelatively sharp leading edge, it is also envisioned that the blade tip207 may be substantially blunt or dull. More particularly, it iscontemplated that the combination of the closure force between the jawmembers 110 and 120 together with the uniquely designed stop members 150a-150 f grip and hold the tissue firmly between the jaw members 110 and120 to permit cutting of the tissue by blade tip 207 even if tip 207 issubstantially blunt. As can be appreciated, designing the blade tip 207blunt eliminates concerns relating to utilizing sharp objects with thesurgical field.

[0162] Once the tissue 420 is divided into tissue halves 420 a and 420b, the jaw members 110 and 120 may be opened by re-grasping the handle40 as explained below. It is envisioned that the knife assembly 200generally cuts in a progressive, uni-directional fashion (i.e.,distally), however, it is contemplated that the knife blade maydimensioned to cut bi-directionally as well depending upon a particularpurpose. For example, the force associated with the recoil of thetrigger spring 75 may be utilized to with a second blade (not shown)which is designed to cut stray tissue wisps or dangling tissue uponrecoil of the knife assembly.

[0163] As best shown in FIG. 32, re-initiation or re-grasping of thehandle 40 again moves t-shaped end 93 of flange 92 generally proximallyalong exit pathway 58 until end 93 clears a lip 61 disposed atoptriangular-shaped members 57 a, 57 b along exit pathway 58. Once lip 61is sufficiently cleared, handle 40 and flange 92 are fully and freelyreleasable from handle 50 along exit pathway 58 upon the reduction ofgrasping/gripping pressure which, in turn, returns the jaw members 110and 120 to the open, pre-activated position.

[0164] From the foregoing and with reference to the various figuredrawings, those skilled in the art will appreciate that certainmodifications can also be made to the present disclosure withoutdeparting from the scope of the present disclosure. For example, it maybe preferable to add other features to the forceps 10, e.g., anarticulating assembly to axially displace the end effector assembly 100relative to the elongated shaft 12.

[0165] It is also contemplated that the forceps 10 (and/or theelectrosurgical generator used in connection with the forceps 10) mayinclude a sensor or feedback mechanism (not shown) which automaticallyselects the appropriate amount of electrosurgical energy to effectivelyseal the particularly-sized tissue grasped between the jaw members 110and 120. The sensor or feedback mechanism may also measure the impedanceacross the tissue during sealing and provide an indicator (visual and/oraudible) that an effective seal has been created between the jaw members110 and 120.

[0166] Moreover, it is contemplated that the trigger assembly 70 mayinclude other types of recoil mechanism which are designed to accomplishthe same purpose, e.g., gas-actuated recoil, electrically-actuatedrecoil (i.e., solenoid), etc. It is also envisioned that the forceps 10may be used to dive/cut tissue without sealing. Alternatively, the knifeassembly may be coupled to the same or alternate electrosurgical energysource to facilitate cutting of the tissue.

[0167] Although the figures depict the forceps 10 manipulating anisolated vessel 420, it is contemplated that the forceps 10 may be usedwith non-isolated vessels as well. Other cutting mechanisms are alsocontemplated to cut tissue 420 along the ideal tissue plane “B-B”. Forexample, it is contemplated that one of the jaw members may include acam-actuated blade member which is seated within one of the jaw memberswhich, upon reciprocation of a cam member, is biased to cut tissue alonga plane substantially perpendicular to the longitudinal axis “A”.

[0168] Alternatively, a shape memory alloy (SMAS) may be employed to cutthe tissue upon transformation from an austenitic state to a martenisticstate with a change in temperature or stress. More particularly, SMAsare a family of alloys having anthropomorphic qualities of memory andtrainability and are particularly well suited for use with medicalinstruments. SMAs have been applied to such items as actuators forcontrol systems, steerable catheters and clamps. One of the most commonSMAs is Nitinol which can retain shape memories for two differentphysical configurations and changes shape as a function of temperature.Recently, other SMAs have been developed based on copper, zinc andaluminum and have similar shape memory retaining features.

[0169] SMAs undergo a crystalline phase transition upon appliedtemperature and/or stress variations. A particularly useful attribute ofSMAs is that after it is deformed by temperature/stress, it cancompletely recover its original shape on being returned to the originaltemperature. This transformation is referred to as a thermoelasticmartenistic transformation.

[0170] Under normal conditions, the thermoelastic martenistictransformation occurs over a temperature range which varies with thecomposition of the alloy, itself, and the type of thermal-mechanicalprocessing by which it was manufactured. In other words, the temperatureat which a shape is “memorized” by an SMA is a function of thetemperature at which the martensite and austenite crystals form in thatparticular alloy. For example, Nitinol alloys can be fabricated so thatthe shape memory effect will occur over a wide range of temperatures,e.g., −270° to +100° Celsius.

[0171] Although the jaw members as shown and described herein depict thejaw members movable in a pivotable manner relative to one another tograsp tissue therebetween, it is envisioned that the forceps may bedesigned such that the jaw members are mounted in any manner which moveone or both jaw members from a first juxtaposed position relative to oneanother to second contact position against the tissue.

[0172] It is envisioned that the outer surface of the end effectors mayinclude a nickel-based material, coating, stamping, metal injectionmolding which is designed to reduce adhesion between the end effectors(or components thereof) with the surrounding tissue during activationand sealing. Moreover, it is also contemplated that the tissuecontacting surfaces 112 and 122 of the end effectors may be manufacturedfrom one (or a combination of one or more) of the following materials:nickel-chrome, chromium nitride, MedCoat 2000 manufactured by TheElectrolizing Corporation of OHIO, inconel 600 and tin-nickel. Thetissue contacting surfaces may also be coated with one or more of theabove materials to achieve the same result, i.e., a “non-stick surface”.Preferably, the non-stick materials are of a class of materials thatprovide a smooth surface to prevent mechanical tooth adhesions. As canbe appreciated, reducing the amount that the tissue “sticks” duringsealing improves the overall efficacy of the instrument.

[0173] Experimental results suggest that the magnitude of pressureexerted on the tissue by the seal surfaces 112 and 122 is important inassuring a proper surgical outcome. Tissue pressures within a workingrange of about 3 kg/cm² to about 16 kg/cm² and, preferably, within aworking range of 7 kg/cm² to 13 kg /cm² have been shown to be effectivefor sealing arteries and vascular bundles. Preferably, the four-barhandle assembly 30, spring 22 and drive assembly are manufactured anddimensioned such that the cooperation of these working elements, i.e.,the four-bar handle assembly 30 (and the internal working componentsthereof), the spring 22 and drive assembly 21, maintain tissue pressureswithin the above working ranges. Alternatively, the handle assembly 30,the spring 22 or the drive assembly 30 may be manufactured anddimensioned to produce tissue pressures within the above working rangeindependently of the dimensions and characteristic of the other of theseworking elements.

[0174] As mentioned above, it is also contemplated that the tissuesealing surfaces 112 and 122 of the jaw members 110 and 120 can be madefrom or coated with these non-stick materials. When utilized on thesealing surfaces 112 and 122, these materials provide an optimal surfaceenergy for eliminating sticking due in part to surface texture andsusceptibility to surface breakdown due electrical effects and corrosionin the presence of biologic tissues. It is envisioned that thesematerials exhibit superior non-stick qualities over stainless steel andshould be utilized on the forceps 10 in areas where the exposure topressure and electrosurgical energy can create localized “hot spots”more susceptible to tissue adhesion. As can be appreciated, reducing theamount that the tissue “sticks” during sealing improves the overallefficacy of the instrument.

[0175] As mentioned above, the non-stick materials may be manufacturedfrom one (or a combination of one or more) of the following “non-stick”materials: nickel-chrome, chromium nitride, MedCoat 2000, Inconel 600and tin-nickel. For example, high nickel chrome alloys, Ni200, Ni201(˜100% Ni) may be made into electrodes or sealing surfaces by metalinjection molding, stamping, machining or any like process. Also and asmentioned above, the tissue sealing surfaces 112 and 122 may also be“coated” with one or more of the above materials to achieve the sameresult, i.e., a “non-stick surface”. For example, Nitride coatings (orone or more of the other above-identified materials) may be deposited asa coating on another base material (metal or nonmetal) using a vapordeposition manufacturing technique.

[0176] One particular class of materials disclosed herein hasdemonstrated superior non-stick properties and, in some instances,superior seal quality. For example, nitride coatings which include, butnot are not limited to: TiN, ZrN, TiAlN and CrN are preferred materialsused for non-stick purposes. CrN has been found to be particularlyuseful for non-stick purposes due to its overall surface properties andoptimal performance. Other classes of materials have also been found toreducing overall sticking. For example, high nickel/chrome alloys with aNi/Cr ratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 112 and 122 made from or coated with Ni200, Ni201(˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

[0177] By way of example, chromium nitride may be applied using aphysical vapor deposition (PVD) process that applies a thin uniformcoating to the entire electrode surface. This coating produces severaleffects: 1) the coating fills in the microstructures on the metalsurface that contribute to mechanical adhesion of tissue to electrodes;2) the coating is very hard and is a non-reactive material whichminimizes oxidation and corrosion; and 3) the coating tends to be moreresistive than the base material causing electrode surface heating whichfurther enhances desiccation and seal quality.

[0178] The Inconel 600 coating is a so-called “super alloy” which ismanufactured by Special Metals, Inc. located in Conroe Tex. The alloy isprimarily used in environments which require resistance to corrosion andheat. The high Nickel content of Inconel makes the material especiallyresistant to organic corrosion. As can be appreciated, these propertiesare desirable for bipolar electrosurgical instruments which arenaturally exposed to high temperatures, high RF energy and organicmatter. Moreover, the resistivity of Inconel is typically higher thanthe base electrode material which further enhances desiccation and sealquality.

[0179] As disclosed herein the present invention relates to the transferof electrosurgical energy though opposing electrically conductivesealing surfaces having different electrical potentials to effect vesselsealing. However, it is also contemplated that the presently disclosedembodiments discussed herein may be designed to seal the tissuestructure using so-called “resistive heating” whereby the surfaces 112and 122 are not necessarily electrically conductive surfaces. Rather,each of the surfaces 112 and 122 is heated much like a conventional “hotplate” such that the surfaces 112 and 122 cooperate to seal the tissueupon contact (or upon activation of a switch (not shown) whichselectively heats each surface 112 and 122 upon activation). With thisembodiment, the resistive heating is achieved using large heating blocks1500 (See FIG. 35A and 35B), resistive heating wire, flexible foilheaters, resistance wire flexible heaters, and/or an externally heatedelement. By controlling the temperature between a range of about 125 toabout 150 degrees Celsius, controlling the pressure between a range ofabout 100 psi to about 200 psi, and regulating the and gap distance Itis also envisioned that the tissue may be sealed and/or fused usingradio frequency (RF) energy. With this embodiment, the electrodes whichtransmit the RF energy may be configured as a large solid blocks or amultiple smaller blocks separated by an insulator. More particularly,the surgeon can selectively regulate the transmission of RF energy to apair of thermally isolated jaw members 110 and 120 which, in turn,transmits the RF energy through the tissue which acts as a resistivemedium. By regulating the RF energy, the temperature of the tissue iseasily controlled. Moreover and as explained in the various embodimentsdescribed above, the closing pressure between the jaw members 110 and120 may be selectively regulated as well by adjusting one or more of theelements of the handle assembly 30, e.g., movable handle 40, fixedhandle 50, flange 92, track 54, etc.

[0180] Preferably, the closing pressure is in the range of about 100 toabout 200 psi. It has been determined that by controlling the RF energyand pressure and maintaining a gap distance “G” in the range of about0.005 millimeters to about 0.015 millimeters between the conductivesurfaces 112 and 122, effective and consistent tissue sealing may beachieved in a broad range of tissue types.

[0181] Alternatively, the forceps 10 may employ any combination of oneor more of the above heating technologies and a switch (not shown) whichallows the surgeon the option of the different heating technology.

[0182] Although the presently described forceps is designed to seal anddivide tissue through standard-sized cannulas, one envisioned embodimentof the present disclosure includes a reduced-diameter shaft 12 and endeffector assembly 100 which is specifically dimensioned to fit through a5 mm cannula. As can be appreciated, utilizing a smaller-sized surgicalinstrument can be extremely beneficial to the patient (i.e., reducedtrauma, healing and scar tissue).

[0183] Preferably, the presently disclosed forceps is designed toelectrically couple to a foot switch (not shown) which allows thesurgeon to selectively control the electrosurgical energy transferred tothe tissue. FIGS. 34A and 34B show an alternate embodiment of thepresent disclosure wherein the forceps is activates via a handswitch1200 located on the trigger assembly 70. More particularly, handswitch1200 includes a pair of wafer switches 1210 which are disposed on eitherside of the trigger 70. The wafer switches 1210 cooperate with anelectrical connector 1220 disposed within the housing 20. It isenvisioned that the wafer switches 1210 are mounted relative to pivotpin 77 such that upon activation of the trigger assembly 70 the waferswitches 1210 are intentionally moved out of electrical contact withconnector 1220. As can be appreciated, this prevents accidentalactivation of the jaw members 110 and 120 during cutting. Alternatively,other safety measures may also be employed, e.g., a cover plate whichinsulates the switches 1210 from the connector 1220 upon actuation ofthe trigger assembly 70, a cut-off switch, etc.

[0184] As mentioned above, it is also envisioned that the knife blade205 may be energized. It is envisioned that the wafer switches could bereconfigured such that in one position, the wafer switches activate thejaw members 110 and 120 upon actuation and in another position, thewafer switches activate the knife blade 205. Alternatively, the waferswitches may be designed as mentioned upon (i.e., with a singleelectrical connector 1220) which energizes both the blade 205 and thejaw members 110 and 120 simultaneously. In this case, the blade 205 mayneed to be insulated to prevent shorting.

[0185] As can be appreciated, locating the handswitch 1200 on theforceps 10 has many advantages. For example, the handswitch reduces theamount of electrical cable in the operating room and eliminates thepossibility of activating the wrong instrument during a surgicalprocedure due to “line-of-sight” activation. Moreover, decommissioningthe handswitch 1200 when the trigger is actuated eliminatesunintentionally activating the device during the cutting process.

[0186] It is also envisioned that the handswitch 1200 may be disposed onanother part of the forceps 10, e.g., the handle assembly 30, rotatingassembly, housing 20, etc. In addition, although wafer switches areshown in the drawings, other types of switches employed which allow thesurgeon to selectively control the amount of electrosurgical energy tothe jaw members or the blade 205, e.g., toggle switches, rockerswitches, flip switches, etc.

[0187] It is also contemplated that in lieu of a knife blade 205, thepresent disclosure may include a so-called “hot-wire” (not shown)interdisposed between the two jaw members 110 and 120 which isselectively activatable by the user to divide the tissue after sealing.More particularly, a separate wire is mounted between the jaw members,e.g., 110 and 120, and is selectively movable and energizable uponactivation of the trigger assembly 70, a handswitch 1200, etc. It isalso envisioned that the “hot wire” may be configured such that the usercan move the wire in an inactivated or activated state which as can beappreciated would allow the user to cut the tissue on a reverse strokeif desired. For example, the hot wire may be secured to one jaw member,e.g., 110, and held in friction fit engagement against the other jawmember, e.g., 120, to allow the tissue or vessel to pass between the jawmembers 110, 120 when grasping and/or when moving the hot wire in aninactivated state distally. Once sealed, the user retracts the wirewhile energizing the hot wire to cut the tissue on the revises stroke.

[0188] It is also contemplated that the hot wire may be segmented witheach end secured to a respective jaw member 110, 120. This would allowthe two opposing hot wires to freely pivot in one direction (i.e., toallow through movement of the tissue between the jaw members 110, 120 inone direction, e.g., upon retraction) and limit the through movement ofthe tissue in the opposite direction.

[0189] In another embodiment, the hot wire may include a hot (i.e.,uninsulated) leading edge and an insulated trailing edge which willprevent charring on the return stroke.

[0190] It is envisioned that the presently disclosed jaw members 110 and120 can include intermittent sealing patterns 1460 a (See FIG. 35C) and1460 b (See FIG. 35D). It is contemplated that the intermittent sealingpatterns 1460 a, 1460 b promote healing by maintaining tissue viabilityand reducing collateral damage to tissue outside the tissue sealingarea. It is know that reduced tissue damage promotes healing by reducingthe chance of tissue necrosis through continued vascularization. Theintermittent sealing patterns 1460 a, 1460 b of FIG. 35A and 35B,respectively, deliver thermal energy to controlled regions, isolated byinsulation from neighboring seal regions. The patterns are preferablydesigned to maximize seal strength yet provide a feasible path forvascularization.

[0191] FIGS. 36-38B show an alternate embodiment of the presentdisclosure wherein the forceps 10 includes a longitudinallyreciprocating tube-like cutter 2000 disposed about the outer peripheryof shaft 12. The cutter 2000 is preferably designed to cut tissue 420along the above-identified ideal seal plane “B-B” after the tissue 420is sealed which, as can be appreciated, typically requires the surgeonto re-grasp the tissue 420 to align the tube cutter 2000 tolongitudinally reciprocate along the intended cutting path of seal plane“B-B”. More particularly, the tube cutter 2000 includes an elongate tube2012 having an interior chamber 2032 which slidingly reciprocates shaft12 and a cutting portion 2014 having a generally U-shaped notched blade2020. Preferably, the tube cutter 2000 is generally thin-walled having athickness of approximately 1.0-5.0 mm.

[0192] A recessed or offset cutting area 2018 is provided adjacent theU-shaped blade 2020 and includes a pair of adjacent cutting edges 2022 aand 2022 b for cutting tissue 420 clamped by jaws members 110 and 120.As can be appreciated, the adjacent cutting edges 2022 a and 2022 b aredisposed along the inner periphery of the U-shaped blade 2020.

[0193] Preferably, the recessed cutting area 2018, i.e., the U-shapedblade 2020, includes a chamfered or beveled surface 2024 which bevelsinwardly from the outer surface of tube 2012 to avoid incidental contactwith surrounding tissue during manipulation and handling, i.e., theinwardly-angled beveled surface 2024 avoids undesirable blade 2020 totissue contact before intentional activation by the surgeon. Further,since intended cutting area 2018 is recessed, forceps 10 can still beused for positioning vessels or tissue 420 being held between jawmembers 110 and 120 without the fear of cutting or nicking the tissue orvessels 420 during use. In one embodiment, the beveled surface 2024 isbeveled at approximately a 30-45 degree angle from the outer surface ofelongate tube 2012.

[0194] The cutting area 2014 also includes two arms 2025 a and 2025 bwhich extend distally from blade 2020. Preferably, the two arms 2025 aand 2025 b lie in substantially the same plane as the outer periphery ofthe elongated tube 2012 and are dimensioned to facilitate introductionor “feeding” of the tissue 420 into the recessed or offset cutting area2018. More particularly, each arm 2025 a and 2025 b includes a straightportion 2030 a and 2030 b, respectively, which both cooperate tointroduce tissue 420 into the cutting are 2018 upon distal movement ofthe tube cutter 2000 towards the tissue 420. A rounded distal end 2033 aand 2033 b may be included on one or both of the distal ends of thestraight portions 2030 a and 2030 b, respectively, to facilitatedelicate positioning the tissue 420 within the cutting area 2018. Forexample and as best shown in FIG. 36, the tissue 420 is initiallyintroduced into the cutting area 2018 between distal ends 2033 a and2033 b. As the cutter 2000 moves distally, i.e., upon activation asexplained in more detail below, the tissue 420 is guided by the straightportions 2030 a and 2030 b into the cutting area 2018 and into contactwith the cutting edges 2022 a and 2022 b.

[0195] Preferably, the cutter 2000 includes a mechanical actuator 2050which activates the cutting 2000 once the tissue 420 is grasped and/orgrasped and sealed between the jaw members 110 and 120. It is envisionedthat the mechanical actuator 2050 can be manually (e.g., trigger) orautomatically activated depending upon a particular purpose or uponactivation of a particular event or timed sequence. The mechanicalactuator 2050 may include one or more safety features, e.g., lockouttabs, electrical circuits, sensor feedback mechanisms (not shown) toprevent accidental activation of the cutter 2000 during grasping orsealing. Simply, the cutter 2000 may be prevented from activation if thejaw members 110 and 120 are disposed in an open configuration. It isalso envisioned that the cutter 2000 may be activated prior to or aftervessel sealing depending upon a particular purpose. Moreover, and asbest illustrated by FIG. 38B, the cutter 2000 may be coupled to a sourceof electrosurgical energy, e.g., RF, ultrasonic, etc., or resistivelyheated to facilitate cutting. For example, a second electrosurgicalgenerator 2060 (or the same generator which energizes the jaw members110 and 120) may be coupled to a lead 2062 which supplieselectrosurgical energy to the cutter 2000. Alternatively, the cutter2000 may simply mechanically cut tissue 420.

[0196] As best illustrated in FIG. 38A, it is also envisioned that thecutter 2000 may include serrated cutting edges 2128 a and 2128 b toenhance cutting. Alternatively, it is also contemplated that the cuttingedges 2028 a and 2028 b may be substantially dull and yet still cut thetissue 420 one sealed. For example, the cutter 2000 may include aspring-like actuator (not shown) which rapidly advances the cuttingedges 2028 a and 2028 b (or 2022 a and 2022 b) through the tissue 420with a predetermined force which is enough to cut the tissue 420 alongthe seal plane “B-B” or between two seals.

[0197] As best shown in FIG. 38B, the cutter may include a coating 2222to facilitate cutting the tissue 420. The coating can include a resinousfluorine containing polymers or polytetrafluoroethylene commonly soldunder the trademark Teflon® (or other Teflon-like substance) tofacilitate mechanical cutting or may be an electrically conductivecoating to facilitate electrosurgical cutting. Alternatively, thecoating 2222 could also be electrically insulative in nature to reduceflashover or thermal spread during activation, or may be designed toreduce sticking. Many of these coatings are described in Applicants'co-pending earlier applications which are all incorporated by referencein their entirely herein, namely, U.S. application Ser. No. 10/116,944,PCT Application Serial No. PCT/US02/01890 and PCT Application Serial No.PCT/US01/11340.

[0198] As best illustrated in the comparison of FIGS. 37A and 37B, thetube cutter 2000 is designed to longitudinally reciprocate alonglongitudinal axis “AA” to cut tissue 420 adjacent the jaw members 110and 120 along the tissue seal plane “B-B”. As can be appreciated, thistypically requires re-grasping the tissue 420 such that the tissuesealing plane “B-B” is disposed on the cutting side of jaw members 110and 120. Alternatively and as shown in FIG. 37B, the cutter 2000 may bedesigned to rotate in a cork-screw-like manner as it moves distallythrough the tissue 420. This may enhance the cutting process. It is alsoenvisioned that a cutter 2000 may be designed such that the cutter 2000is disposed within a recessed portion of one of the two jaw members,e.g., 110, such that the cutter 2000 simply rotates through the tissue420 or around the jaw member 110 without moving along the longitudinalaxis “M” (or only moving minimally along axis “M”).

[0199] The tube cutter 2000 also includes an elongated channel 2040disposed on the opposite side of the unshaped blade 2020. The channel2040 is necessary to facilitate unimpeded distal movement of the cutter2000 over the jaw members 110 and 120 and allow the opposite (i.e.,uncut) end of the tissue 420 to move freely proximally past the jawmembers 110 and 120 during the cutting process. Alternatively, thecutter 2000 may be designed such that the cutter 2000 is generallyarcuate or sleeve-like and is not tubular in fashion. This design alsoallows free proximal movement of the uncut tissue 420 end past the jawmembers 110 and 120 during cutting.

[0200]FIGS. 39A and 39B shows yet another embodiment of the forceps 3000of the present disclosure wherein a unilateral jaw closure mechanism3010 is utilized to grasp tissue 420. More particularly, the forceps3000 includes a first or upper jaw member 3110 and a second or lower jawmember 3120 disposed at the distal end of an elongated shaft 3012. Theunilateral closure mechanism 3010 is designed for use with laparoscopic,bipolar or monopolar electrosurgical devices as described herein.

[0201] The unilateral closure mechanism 3010 includes one stationary jawmember 3120 mounted to the shaft 3012 and pivoting jaw member 3110mounted about a pivot pin 3160 attached to the shaft 3012. Areciprocating sleeve 3130 is disposed about the outer periphery of theshaft 3012 and is preferably remotely operable by a user. The pivotingjaw 3110 includes a detent or protrusion 3140 which extends from jawmember 3110 through an aperture 3150 disposed within the outer sleeve3130. The pivoting jaw 3110 is actuated by sliding the sleeve 3130axially along the outside of shaft 3012 such that the aperture 3150abuts against the detent 3140 on the pivoting jaw 3110. Pulling thesleeve proximally closes the jaw members 3110 and 3120 about tissue 420grasped therebetween and pushing the sleeve 3130 distally open the jawmembers 3110 and 3120 for approximation.

[0202] As best illustrated in FIGS. 39B and 39C of the presentdisclosure, a blade or knife channel 3170 runs through the center of thejaw members 3110 and 3120 such that a blade 3190 can cut the tissue 420grasped between the jaw members 3110 and 3120 only while the jaws areclosed. More particularly, the blade 3190 can only be advanced throughthe tissue 420 when the jaw members 3110 and 3120 are closed thuspreventing accidental or premature activation of the blade 3190 throughthe tissue 420. Put simply, the knife channel 3170 is blocked when thejaws members 3110 and 3120 are opened and aligned for activation whenthe jaw members 3110 and 3120 are closed. In addition, the unilateralclosure mechanism 3010 can be structured such that electrical energy canbe routed through the sleeve 3130 at the protrusion contact 3180 pointwith the sleeve 3130 or using a “brush” or lever (not shown) to contactthe back of the moving jaw 3110 when the jaw closes. It is envisionedthat the jaw member 3110 may be closed and energized simultaneously orindependently by a separate actuator (not shown).

[0203] More particularly, when the sleeve 3130 is pushed distally, theproximal most portion of the aperture 3150 abuts against the protrusionto pivot the jaw member 3110 into the open configuration. Preferably,the point of contact 3155 between the aperture and the protrusion 3140is insulated to prevent premature activation of the forceps 3000. Whenthe sleeve is pulled proximally, the distal most portion of the sleeveabuts against the protrusion 3140 and closes the jaw member 3110.Preferably, the distal most contact 3180 and provides electricalcontinuity to the jaw members 3110 and 3120 through the sleeve 3130 forsealing purposes.

[0204] As can be appreciated, these designs provide at least twoimportant safety features: 1) the blade 3190 cannot extend while the jawmembers 3110 and 3120 are opened; and 2) electrical continuity to thejaw members 3110 and 3120 is made only when the jaws are closed.

[0205] It is envisioned that the moving jaw 3110 may also function asthe blade 3190 with mechanical energy, electrical energy or acombination of both used for cutting. For example, the blade channel3170 could include a mechanical cutting mechanism or anelectromechanical cutting mechanism (as described elsewhere herein)which is separately actuated once the jaw members 3110 and 3120 areclosed about the tissue 420. It is also envisioned that the sleeve 3130may be biased against a spring assembly (not shown) to provide increasedmechanical advantage during activation. It is contemplated that variousmechanisms may be employed to provide a mechanical advantage to increasethe closure force between jaw members 3110 and 3120, e.g., two, threeand/or fourbar linkages, hydraulic mechanisms, electro-assistedactuators, cam mechanisms, gear assemblies, etc.

[0206] Another embodiment of the present disclosure includes the use ofa hard anodized aluminum 3200 with or without the use of a syntheticsealed coating 3300 (See FIGS. 39A and 39B) made from a resinousfluorine containing polymers or polytetrafluoroethylene commonly soldunder the trademark Teflon® on electrically non-conductive components ofone or both of the jaw members 3110 and 3120 (i.e., the areassurrounding the conductive surfaces) to control the electrical pathbetween the two jaw members 3110 and 3120 during electrosurgicalactivation and reduce sticking. Other materials which tend to reducetissue adherence include: nickel-chrome, chromium nitride, Ni200, Ni201,inconel 600, tin-nickel. It is envisioned that utilizing a hard anodizedaluminum 3200 on at least one jaw member's 3110 non-sealing surfaceelectrically isolates the jaw members 3110 and 3120 from one another andconfines the electrosurgical energy between the conductive sealingsurfaces. The non-stick coating 3300 reduces undesirable sticking oftissue 420 to jaw components during the sealing process.

[0207] Preferably, the hard anodized aluminum 3200 has a high dielectricstrength and good wear properties and has a thickness of about 0.001 toabout 0.003 inches. It has been found that electrically insulating thealuminum jaws 3110 and 3120 from other surrounding components confinesthe electrical path to between the jaw members 3110 and 3120 andeliminates alternate current paths which can result in collateral tissuedamage.

[0208] Although the subject apparatus has been described with respect topreferred embodiments, it will be readily apparent to those havingordinary skill in the art to which it appertains that changes andmodifications may be made thereto without departing from the spirit orscope of the subject apparatus.

[0209] While several embodiments of the disclosure have been shown inthe drawings, it is not intended that the disclosure be limited thereto,as it is intended that the disclosure be as broad in scope as the artwill allow and that the specification be read likewise. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. An endoscopic bipolar forceps, comprising: anelongated shaft having opposing jaw members at a distal end thereof, thejaw members being movable relative to one another from a first positionwherein the jaw members are disposed in spaced relation relative to oneanother to a second position wherein the jaw members cooperate to grasptissue therebetween; a source of electrical energy connected to each jawmember such that the jaw members are capable of conducting energythrough tissue held therebetween to effect a seal; and a generallytube-like cutter slidably engaged about said elongated shaft which isselectively movable about said elongated shaft to engage and cut tissueon at least one side of the jaw members while the tissue is engagedbetween jaw members.
 2. An endoscopic bipolar forceps according to claim1 wherein said cutter includes a U-shaped notched blade.
 3. Anendoscopic bipolar forceps according to claim 2 wherein said U-shapednotched blade is recessed from an outer periphery of said cutter.
 4. Anendoscopic bipolar forceps according to claim 2 wherein said U-shapednotched blade includes a bevel.
 5. An endoscopic bipolar forcepsaccording to claim 2 wherein said U-shaped notched blade includesopposing serrated cutting edges.
 6. An endoscopic bipolar forcepsaccording to claim 1 wherein said cutter includes a remotely operableactuator for selectively deploying said cutter to sever tissue.
 7. Anendoscopic bipolar forceps according to claim 6 wherein said actuator isa trigger.
 8. An endoscopic bipolar forceps according to claim 6 whereinsaid actuator includes means for rapidly advancing said cutter to severtissue.
 9. An endoscopic bipolar forceps according to claim 8 whereinsaid cutter includes a substantially dull U-shaped notched blade whichis rapidly advanced through the tissue.
 10. An endoscopic bipolarforceps according to claim 1 wherein said cutter rotates as said cuttersevers tissue on at least one side of the jaw members while the tissueis engaged between jaw members.
 11. An endoscopic bipolar forcepsaccording to claim 1 wherein said cutter is connected to a source ofelectrosurgical energy and said cutter severs tissue in anelectrosurgical manner.
 12. An endoscopic bipolar forceps according toclaim 1 wherein said cutter is heated by a resistive heating source. 13.An endoscopic bipolar forceps according to claim 1 wherein said cutterincludes a non-stick coating to reduce tissue adhesion during cutting.14. An endoscopic bipolar forceps according to claim 1 wherein saidcutter includes a cutting area having a U-shaped notched blade at aproximal end thereof and a pair of arms at a distal end thereof, saidarms being dimensioned to feed tissue into said cutting area intocontact with said U-shaped notched blade upon distal movement of saidcutter.
 15. An endoscopic bipolar forceps, comprising: an elongatedshaft having opposing jaw members at a distal end thereof, one of thejaw members being movable relative to the other jaw member from a firstposition wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween; an electrically conductive outersleeve which at least partially surrounds said shaft, said outer sleevemechanically cooperating with said movable jaw member to pivot said jawmember from the first to second positions; and means for selectivelymoving said outer sleeve to electrosurgically energize and pivot saidjaw members.
 16. An endoscopic bipolar forceps according to claim 15wherein said movable jaw member includes a protrusion which mechanicallyinterfaces with said outer sleeve such that when said sleeve moves in afirst direction, said movable jaw member pivots to the first positionand is electrically isolated from said outer sleeve and when said sleevemoves in a second direction, said movable jaw member pivots into thesecond position and said outer sleeve electrosurgically energizes saidmovable jaw member.
 17. An endoscopic bipolar forceps according to claim15 wherein at least one of said jaw members includes a knife channel forreciprocating a knife therethrough.
 18. An endoscopic bipolar forcepsaccording to claim 17 wherein said distal end of said elongated shafthouses said knife within a corresponding knife cavity.
 19. An endoscopicbipolar forceps according to claim 18 wherein said knife is preventedfrom reciprocating through said knife channel when said jaw member is inthe first position and said knife channel and said knife cavity are outof alignment.
 20. An endoscopic bipolar forceps according to claim 15wherein said jaw members include opposing conductive sealing surfacesdisposed on the inner facing surfaces of said jaw members and wherein atleast one of the jaw members is made from a hard anodized aluminumhaving high dielectric properties.
 21. An endoscopic bipolar forcepsaccording to claim 15 wherein each jaw member includes an outerperipheral surface manufactured from a material which reduces tissueadherence, the outer peripheral surface being selected from a group ofmaterials consisting of: TiN, ZrN, TiAlN, CrN, Ni200, Ni201, inconel600, and resinous fluorine containing polymers orpolytetrafluoroethylene.